winbugs: array index is greater than array upper bound for model with data type kategoric (ordinal)

Question

I need help to find the error in my WINBUGS code (v. 1.4.3).

While in the "Model Specification" step, the model looks syntatically correct. However, in my attempt to load the data, I got this error:

array index is greater than array upper bound for a

Could someone please help me? My model is provided below:

{ 
for (i in 1:n) 
{ 
y[i]~dcat(p[i,1:4]) 
p[i,1] <- p.cum[i,1] 
p[i,2] <- p.cum[i,2]-p.cum[i,1] 
p[i,3] <- p.cum[i,3]-p.cum[i,2] 
p[i,4] <- 1 - p.cum[i,3] 
} 
for (i in 1:n) 
{ 
for (k in 1:8) 
{ 
p.cum[i,k]<-1/(1+exp(pi[i,k])) 
pi[i,k]<- -a[k]+b.x1*x1[i]+b.x2*x2[i]+b.x3*x3[i]+b.x4*x4[i]+b.x5*x5[i]+b.x6*x6[i]+b.x7*x7[i]+b.x8*x8[i]
} 
} 
a[1]<-c[1] 
a[2]<-a[1]+c[2] 
a[3]<-a[2]+c[3] 
c[1] ~ dnorm(0.0,1.0E-4)#Prior for intercept 
c[2] ~ dnorm(0.0,1.0E-4)#Prior for intercept 
c[3] ~ dnorm(0.0,1.0E-4)#Prior for intercept 
b.x1~dnorm(0.0,1.0E-4)#Prior for slope ofx1 
b.x2~dnorm(0.0,1.0E-4)#Prior for slope ofx2 
b.x3~dnorm(0.0,1.0E-4)#Prior for slope ofx3 
b.x4~dnorm(0.0,1.0E-4)#Prior for slope ofx4 
b.x5~dnorm(0.0,1.0E-4)#Prior for slope ofx5 
b.x6~dnorm(0.0,1.0E-4)#Prior for slope ofx6 
b.x7~dnorm(0.0,1.0E-4)#Prior for slope ofx7 
b.x8~dnorm(0.0,1.0E-4)#Prior for slope ofx8 
or.x1<-exp(b.x1) 
or.x2<-exp(b.x2) 
or.x3<-exp(b.x3) 
or.x4<-exp(b.x4)
or.x5<-exp(b.x5) 
or.x6<-exp(b.x6) 
or.x7<-exp(b.x7) 
or.x8<-exp(b.x8) 
}

#data 
list( n = 770,
y=c(4,4,4,4,4,4,4,4,3,3,4,2,4,4,3,1,3,4,4,1,3,1,4,4,1,4,3,4,4,3,4,2,1,4,3,4,4,4,1,4,4,4,3,4,3,4,3,4,4,4,4,4,3,3,4,4,4,4,4,4,3,2,4,4,3,3,3,4,1,3,3,1,1,4,4,4,3,4,1,1,4,2,4,3,4,3,1,4,4,1,3,3,4,1,4,1,4,4,1,3,1,4,3,4,4,4,4,4,3,4,4,3,1,1,3,4,3,1,4,4,1,3,4,4,3,4,4,4,4,3,3,4,3,4,3,4,4,1,4,1,3,3,3,3,4,1,1,3,4,4,1,2,3,2,3,4,4,1,4,1,4,4,4,4,4,4,1,3,4,4,3,4,4,4,3,4,3,3,1,4,4,1,4,4,3,2,1,4,1,1,4,4,1,3,3,3,3,1,4,4,4,4,3,3,4,3,3,1,4,1,3,4,1,1,1,4,1,4,3,4,4,4,3,3,4,1,4,3,1,4,4,4,4,4,4,1,4,4,4,1,3,1,4,3,3,1,4,4,4,3,3,4,1,4,1,2,1,1,1,1,4,4,1,2,1,1,1,4,4,4,1,4,1,3,3,1,3,2,3,1,1,1,4,4,4,3,4,3,1,3,1,3,1,3,1,1,4,3,4,3,4,1,1,4,4,3,4,4,4,2,1,1,3,3,1,4,3,1,1,3,3,1,4,2,4,4,4,4,1,3,2,1,1,1,4,4,4,3,1,1,3,1,4,1,4,4,4,1,1,3,1,3,3,4,4,4,4,1,4,4,3,4,4,4,4,4,4,4,4,1,4,1,1,1,4,2,4,4,3,1,3,4,1,1,1,4,4,2,2,4,4,4,1,2,4,4,1,4,3,2,1,4,3,4,4,3,1,1,4,3,1,4,3,4,3,1,1,1,4,1,1,4,1,1,3,1,3,1,1,1,1,1,1,4,1,4,3,4,1,4,4,4,4,1,3,1,4,4,4,1,1,2,4,4,1,1,1,1,4,4,4,4,3,3,3,1,1,4,4,1,1,4,4,3,4,3,4,3,3,4,4,1,4,4,4,4,1,1,3,1,1,3,4,4,1,2,3,3,1,3,4,3,4,3,1,4,3,4,1,3,1,4,1,3,1,4,3,2,1,3,1,3,1,4,3,4,3,3,1,1,4,3,4,4,1,4,1,4,4,4,4,1,3,4,4,4,4,1,3,4,3,3,4,1,3,1,4,1,4,4,1,1,2,2,4,4,4,1,3,4,3,1,4,1,1,1,3,4,1,3,4,4,1,3,4,4,1,4,1,4,3,3,4,3,2,1,3,1,3,1,1,3,4,4,3,1,3,4,4,4,1,1,4,3,4,2,1,4,3,4,4,1,1,1,4,4,4,4,4,1,1,4,3,1,4,4,4,4,4,4,3,4,3,3,4,4,3,4,4,1,1,1,1,4,3,4,1,1,1,1,4,3,3,1,1,3,4,4,4,3,3,4,3,4,3,3,1,4,4,4,3,4,4,3,4,4,3,4,3,4,4,3,4,4,4,4,1,1,3,3,4,4,3,3,3,1,3,4,4,4,4,4,3,3,4,4,4,4,4,3,4,4,4,4,4,3,4,3,4,3,3,4,4,3,3,4,4,1,4,4,1,4,4,3,4,4,3,1,4,4,2,3,4,1,3,4,4,4,3,1,4,3,4,4,4,4,4,1,3,4),

x1=c(3,2,5,2,3,5,4,5,5,4,5,4,5,4,4,5,4,4,5,3,5,5,5,3,3,5,5,3,2,5,3,5,3,5,4,2,3
,5,5,5,3,4,2,4,3,5,3,5,5,5,2,3,5,5,5,5,5,2,3,4,2,5,5,4,5,5,2,5,5,5,3
,5,5,4,5,4,4,5,4,4,5,5,3,5,2,5,5,5,4,4,3,4,2,5,5,5,5,5,4,5,3,5,5,3,
5,5,5,5,5,5,5,4,4,5,5,5,5,5,5,2,2,5,5,4,5,5,5,3,5,2,4,5,3,3,3,5,5,5,5,3,2,2,5,4,5,5,5,5,4,5,2,3,3,5,4,2,3,3,4,3,5,4,5,4,5,3,3,3,5,2,5,2,5,5,4,3,5,2,5,3,4,3,4,5,2,3,5,2,5,3,2,3,3,5,2,4,3,5,5,3,2,5,4,5,5,3,2,5,5,5,2,5,2,4,3,5,5,5,5,2,5,2,4,5,3,5,4,2,5,5,4,5,2,5,3,5,3,5,5,5,5,5,3,5,4,2,5,5,5,4,2,5,5,4,5,5,5,5,5,5,5,5,3,5,4,5,5,3,5,3,5,3,5,2,5,5,4,5,4,3,5,2,4,5,4,4,2,5,3,4,5,4,5,2,5,4,5,5,5,5,3,5,5,5,4,5,5,5,5,5,3,5,5,4,4,3,2,5,4,3,5,5,5,5,5,5,5,5,5,4,5,4,4,5,5,5,5,3,5,3,5,2,5,5,3,5,5,5,5,4,5,5,5,4,5,2,4,3,5,5,4,4,4,5,5,4,5,2,5,5,5,4,4,5,3,5,4,5,2,5,5,2,5,4,4,5,5,5,5,4,4,5,5,5,3,5,4,5,2,2,5,5,5,2,5,4,5,5,5,2,3,4,5,4,2,2,3,5,5,5,3,3,5,4,5,5,2,5,3,5,3,5,5,5,5,2,5,4,5,5,4,3,5,5,4,3,5,5,2,5,4,4,4,3,5,5,5,3,3,4,5,5,2,5,5,5,5,2,4,2,5,3,5,4,5,2,5,5,5,5,3,5,5,5,5,4,5,4,4,3,5,5,5,5,5,5,5,5,2,2,2,3,3,4,5,5,3,5,3,5,5,5,5,5,4,5,5,5,4,5,5,4,5,5,4,5,5,3,5,3,5,3,5,2,5,2,5,5,5,4,4,5,2,5,3,5,4,5,5,5,5,5,5,5,4,4,5,3,5,2,5,3,5,4,5,5,3,5,4,2,5,3,5,5,5,3,4,5,4,2,5,5,5,5,4,5,5,5,3,5,3,3,4,5,5,5,2,5,4,5,5,2,5,2,3,5,5,5,5,5,5,5,5,3,5,5,5,5,5,4,5,2,3,3,5,4,5,5,5,3,4,4,5,2,4,5,5,5,5,2,2,5,5,4,2,2,3,5,5,4,5,2,4,5,4,5,3,4,2,4,2,3,4,5,3,5,5,4,5,4,4,3,5,5,5,5,3,5,5,5,4,5,3,4,4,4,5,5,5,5,3,5,5,5,4,3,5,3,4,5,3,5,4,5,5,4,2,4,5,5,5,5,5,3,5,5,5,4,5,4,4,4,3,5,2,5,5,4,5,2,5,5,2,3,2,5,5,5,3,5,4,5,4,5,5,5,5,5,2,2,3,5,5,5,3,5,5,5,3,5,5,4,5,5,5,3,3,2,4,5),

x2=c(3,2,5,2,3,5,3,5,5,4,5,5,5,4,4,5,4,4,5,3,5,5,5,3,3,5,4,3,2,5,3,5,3,5,5,3,3,5,5,5,3,5,2,5,5,5,3,5,5,5,3,3,5,5,5,5,5,2,3,4,2,5,5,4,5,5,3,5,5,5,3,5,5,4,3,5,4,5,4,4,5,3,2,5,2,5,5,5,5,5,4,4,2,5,5,5,5,5,5,5,3,5,5,3,5,5,5,5,5,5,5,4,5,5,5,5,5,5,5,2,2,5,5,4,5,5,5,4,5,2,3,5,5,3,3,5,5,5,5,5,2,3,5,5,5,5,5,5,5,2,2,3,5,5,4,5,3,4,4,5,5,4,2,2,5,4,3,4,5,2,5,2,5,5,4,4,5,2,5,3,4,3,5,5,2,5,5,2,5,3,2,4,4,5,5,5,3,5,5,3,4,5,5,5,5,5,3,5,5,5,2,5,2,4,4,5,5,5,5,2,5,2,4,5,5,5,4,2,5,5,4,5,2,5,2,5,3,5,5,5,5,5,4,5,5,5,5,5,5,5,2,5,5,5,5,5,5,5,5,5,3,4,5,5,4,5,5,3,5,3,5,3,5,2,5,5,4,5,4,3,5,2,4,5,4,4,2,5,3,4,5,4,5,2,5,4,5,5,5,5,4,5,5,5,4,5,5,5,5,5,3,5,5,4,4,3,3,5,4,4,5,4,5,5,5,5,5,5,5,5,5,4,4,5,5,5,5,5,5,4,5,2,5,5,3,5,5,5,5,4,5,5,5,4,5,3,4,4,5,5,3,4,4,5,5,4,5,3,5,5,5,5,4,5,3,5,5,2,4,5,5,5,5,4,4,5,5,5,5,5,3,5,5,5,3,5,4,5,2,2,5,5,5,2,5,4,5,5,5,2,5,4,5,5,3,2,3,5,2,5,3,4,5,4,5,5,2,3,5,5,3,5,5,5,5,2,5,4,5,5,4,3,5,5,4,3,5,5,5,5,4,4,4,3,5,5,5,5,3,4,5,3,2,5,5,5,5,2,4,2,5,3,5,4,5,3,5,5,5,5,4,3,5,5,2,5,4,4,5,5,5,5,5,5,5,5,5,5,5,4,3,4,4,4,5,5,3,5,3,5,5,5,5,5,4,5,5,5,4,5,5,5,5,5,5,5,2,3,5,3,5,3,5,2,5,2,5,5,5,4,4,5,5,5,4,5,4,5,5,5,5,5,5,5,4,4,5,5,5,2,5,4,5,4,5,5,3,5,4,4,5,3,5,5,3,3,4,5,4,3,5,5,5,5,4,5,5,5,4,5,4,5,4,5,5,5,2,4,4,5,5,5,5,4,3,5,5,5,5,5,5,5,5,3,5,5,5,5,5,4,5,5,4,4,5,3,3,5,5,3,5,4,5,5,5,5,5,5,3,3,2,5,5,4,2,2,3,5,5,5,5,2,4,5,5,5,3,5,4,4,5,4,4,5,3,5,5,4,5,4,4,4,5,5,5,5,2,5,5,5,4,5,2,4,5,4,5,5,5,5,3,5,5,5,4,3,5,3,4,5,3,5,4,5,5,4,2,4,5,5,5,5,5,4,5,5,5,3,5,4,4,4,4,5,2,5,5,5,5,2,5,5,5,4,2,5,5,5,3,5,5,5,4,5,5,5,5,5,2,2,5,5,5,5,5,5,5,5,4,5,5,5,5,5,5,3,3,3,4,5),

x3=c(4,4,5,4,5,5,3,5,5,4,5,5,4,4,4,5,4,5,5,3,5,5,5,5,3,5,4,4,5,5,3,5,3,5,3,4,4,5,5,5,3,3,3,5,4,5,4,5,5,5,5,5,5,5,5,5,5,4,4,4,2,5,5,4,5,5,3,5,5,5,3,5,3,5,5,4,4,5,4,4,5,4,5,5,5,5,5,5,5,4,4,4,4,5,5,5,5,3,5,4,5,5,5,3,5,5,3,4,5,4,5,4,4,5,5,5,5,4,5,5,4,3,5,3,3,5,5,3,5,5,4,5,5,5,4,5,5,5,5,3,3,3,2,5,5,5,5,5,4,5,4,2,5,5,4,4,5,5,4,2,5,4,4,3,5,3,4,4,3,2,5,3,5,5,4,5,5,2,4,4,4,4,5,5,3,4,4,4,5,4,2,4,5,5,5,4,4,5,5,3,4,5,4,5,4,3,4,5,5,5,5,5,5,5,4,4,5,3,5,2,5,3,4,5,5,4,4,3,5,3,4,5,4,5,4,5,3,5,4,5,5,5,5,5,4,5,5,5,5,5,5,5,5,4,5,5,4,5,5,5,4,5,5,5,5,5,2,5,5,4,5,4,5,3,5,5,5,5,5,5,5,4,4,5,4,4,2,5,3,4,4,5,5,3,5,4,5,5,5,5,4,5,5,5,4,5,4,5,4,5,3,5,3,3,3,4,5,5,4,3,5,4,5,5,5,5,5,4,5,4,5,4,4,5,5,2,5,4,5,4,5,2,5,5,3,2,5,5,5,4,5,3,5,5,5,4,4,4,5,4,4,4,4,5,5,4,5,5,5,5,4,4,4,5,3,5,4,5,5,5,5,4,5,4,4,5,5,5,4,4,4,5,5,5,3,5,4,5,5,4,5,5,5,4,5,4,5,5,5,2,5,4,5,4,4,4,2,5,4,4,3,5,5,5,5,5,5,5,5,5,3,4,5,5,5,5,4,4,5,5,45,5,5,4,4,5,5,2,5,4,5,4,4,5,5,5,3,4,4,5,4,5,5,5,5,5,2,4,2,5,5,5,2,5,4,5,5,5,2,4,4,5,5,3,4,4,4,4,5,5,5,5,5,5,5,5,5,4,5,5,5,4,4,5,5,3,5,4,5,5,5,5,5,4,5,5,5,4,5,5,4,5,5,3,5,3,5,5,3,5,4,5,3,5,3,5,5,5,5,5,5,4,5,4,5,4,5,5,4,5,5,5,5,4,4,5,3,52,5,3,5,3,5,5,5,5,4,2,5,3,5,5,4,5,4,5,4,3,4,5,5,4,4,5,5,5,4,3,3,3,4,2,5,5,4,5,5,5,5,4,5,3,3,5,5,5,5,5,5,5,4,5,5,5,5,5,3,4,5,5,4,3,5,4,5,5,5,5,5,4,5,5,5,5,5,5,5,3,4,5,5,4,4,4,5,5,3,5,5,4,4,5,5,5,3,4,3,5,5,4,4,5,4,5,4,4,5,4,4,5,5,5,5,5,4,5,4,5,4,5,5,4,5,4,3,5,4,5,3,5,55,4,4,5,5,5,5,4,5,4,4,5,4,4,4,5,5,5,2,5,4,5,4,5,5,5,4,4,4,5,5,5,5,5,4,5,2,5,5,4,4,3,5,5,5,5,5,4,5,5,5,5,5,5,5,4,3,4,4,4,5,5,5,4,5,3,5,5,5,5,5,5,4,3,2,4,3),


x4=c(5,5,5,4,5,5,3,5,5,4,5,5,4,4,3,5,4,5,5,5,5,5,5,5,3,5,3,5,3,5,3,5,3,5,3,4,5,5,5,5,3,3,3,5,3,5,4,5,5,5,2,5,5,5,5,5,3,5,5,4,5,5,5,4,5,5,4,5,5,5,3,5,5,5,4,4,4,5,4,4,5,4,5,5,5,5,5,5,5,5,4,5,4,5,5,4,4,5,5,4,5,5,5,4,5,5,5,5,5,4,5,5,4,5,5,5,5,4,5,4,4,3,5,2,5,5,5,4,5,5,5,5,4,5,1,5,5,5,5,5,4,2,1,5,5,5,5,5,4,5,4,2,4,5,4,4,5,5,4,2,5,3,1,4,5,4,4,3,3,3,5,4,5,5,4,5,5,2,5,5,4,4,5,5,5,4,4,5,5,5,2,5,5,5,5,4,5,5,5,3,2,4, 5,5,5,2,5,5,5,4,5,5,4,5,4,4,5,5,5,2,5,3,4,5,5,5,5,3,5,5,4,5,5,5,1,5,3,5,4,5,5,5,5,5,4,5,5,5,5,4,5,5,1,5,5,5,5,5,5,5,5,4,5,4,3,5,3,5,5,3,5,5,5,3,5,1,5,5,5,5,5,5,5,5,4,4,2,5,4,5,5,5,5,3,5,4,5,5,5,5,5,3,5,5,4,5,5,5,5,1,3,5,2,4,5,5,5,5,4,5,5,5,5,5,5,5,5,4,5,4,5,4,4,1,5,2,5,4,5,4,5,5,5,1,4,3,5,5,5,4,5,3,5,5,5,3,4,5,5,4,5,4,4,5,5,4,5,5,5,5,5,5,4,5,3,5,5,4,5,5,5,2,5,4,3,5,4,5,4,4,4,5,5,1,4,5,5,5,5,4,5,4,5,4,5,4,5,5,5,3,3,5,5,5,4,3,5,5,4,3,4,5,5,5,5,5,5,3,5,5,3,4,5,5,5,5,5,4,5,5,4,5,5,5,4,3,5,3,5,5,4,5,5,3,5,5,5,2,5,4,5,4,5,5,5,4,5,2,4,2,5,5,5,2,5,4,5,5,5,1,4,5,5,5,3,5,5,4,4,5,5,5,5,5,5,5,5,5,4,5,5,4,5,
5,5,5,3,5,1,5,5,5,5,5,4,5,5,1,5,5,5,5,5,5,5,5,3,3,5,3,5,5,5,4,5,4,5,2,5,5,5,5,3,5,4,5,4,5,5,4,5,5,5,5,4,4,4,3,5,1,5,3,5,4,5,5,5,5,4,5,5,3,5,5,4,4,4,5,4,5,5,5,5,5,4,5,5,5,5,4,5,3,4,2,5,5,4,5,5,5,5,5,5,3,3,5,5,5,5,4,5,1,5,5,5,5,5,5,3,4,5,5,4,4,5,5,5,5,5,2,5,5,5,5,4,5,5,5,3,5,5,5,5,4,4,4,5,5,4,5,5,3,5,5,5,5,3,4,4,4,5,4,4,5,4,5,5,4,5,5,1,5,5,5,2,5,5,5,5,5,4,5,5,4,5,4,5,5,4,5,3,4,5,5,5,3,5,5,5,5,5,5,4,5,5,5,5,4,5,5,5,1,5,3,5,5,5,5,1,4,4,5,5,5,2,5,5,5,5,5,5,5,4,5,5,5,5,5,5,1,4,5,4,5,5,5,5,5,3,2,4,5,5,5,5,4,4,5,3,5,3,5,5,5,5,4,3,2,4,3),

x5=c(4,5,5,5,5,4,3,5,5,4,5,5,5,4,4,5,4,4,5,5,5,5,5,4,3,5,4,4,5,5,3,5,4,5,4,4,4,5,5,5,3,4,3,5,3,5,3,5,5,5,5,5,5,5,5,5,2,5,5,4,4,5,5,4,5,5,4,5,5,5,3,5,5,5,5,4,5,5,4,4,5,3,4,5,5,5,5,5,5,4,3,5,5,5,5,5,4,3,5,5,4,5,5,5,5,5,5,4,5,4,5,4,5,5,5,5,5,5,5,3,5,3,5,3,5,5,5,4,5,5,4,5,5,5,5,5,5,5,5,3,5,3,4,5,4,5,5,5,4,5,3,2,4,5,4,4,5,5,4,5,5,5,4,4,5,4,5,4,3,4,5,3,5,5,4,5,5,2,2,5,4,4,5,5,2,5,5,5,5,3,2,5,5,5,5,5,5,5,5,3,5,5,5,5,5,2,3,5,5,5,5,5,5,5,4,4,5,4,5,3,5,3,4,5,5,3,4,3,3,5,5,5,3,5,4,5,3,5,2,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,4,4,5,5,5,4,2,5,5,3,5,3,5,5,4,5,4,5,5,5,5,5,4,5,4,4,2,5,3,4,4,5,5,3,5,4,4,5,5,5,4,3,5,5,4,5,3,5,5,5,3,5,2,4,3,5,5,5,4,4,5,4,5,3,5,4,5,4,5,4,5,4,4,5,5,2,5,4,5,3,5,2,5,5,4,4,5,5,5,5,5,4,5,5,5,3,4,4,5,4,4,4,4,5,5,4,5,5,5,5,4,4,4,5,2,5,5,5,5,5,5,4,5,5,5,5,5,5,4,4,4,5,5,5,3,5,3,5,4,5,5,5,5,4,5,4,5,5,5,3,3,4,4,5,4,3,5,5,4,4,4,5,5,4,5,5,4,3,5,5,3,5,5,5,5,5,3,4,5,5,4,5,5,5,4,3,5,5,5,5,5,5,4,4,5,5,5,5,4,4,5,4,5,5,5,5,5,2,4,2,5,5,5,2,5,4,5,5,5,5,4,2,5,5,3,5,5,4,4,5,5,5,5,5,5,5,5,5,4,5,5,5,4,5,5,5,4,5,3,5,5,5,5,5,4,5,5,5,5,5,5,4,5,5,3,5,2,5,5,3,5,4,5,3,5,3,5,5,5,5,5,5,5,5,4,5,4,5,5,4,5,5,5,5,4,4,5,5,5,2,5,3,5,4,5,5,5,5,3,4,5,3,5,5,4,4,4,5,4,3,5,5,5,3,4,5,5,5,4,5,4,4,4,5,5,5,5,5,4,5,5,5,5,3,4,5,5,5,5,4,5,5,4,5,5,5,5,5,2,4,5,5,4,4,5,5,5,5,5,5,5,4,5,5,4,5,5,5,5,5,4,5,5,4,4,4,4,5,5,5,5,3,4,5,4,5,3,2,3,4,5,5,4,5,4,4,5,4,5,4,4,5,5,5,2,5,4,5,3,5,4,5,4,4,4,4,4,5,4,5,3,4,5,5,5,4,5,4,5,5,4,5,4,4,5,4,5,4,5,5,5,5,5,5,5,4,5,5,5,4,4,4,4,5,2,5,5,4,4,3,5,5,4,4,5,5,5,5,5,5,4,5,5,5,5,5,5,5,4,2,4,5,5,5,5,5,4,5,3,5,5,5,5,5,5,5,3,2,4,3),

x6=c(2,3,5,4,5,5,3,5,5,3,5,4,5,4,4,5,4,4,5,5,5,5,5,4,3,5,4,4,4,5,3,5,4,5,5,4,3,3,5,5,3,3,3,4,2,5,2,5,5,5,5,4,5,5,5,5,5,4,3,2,3,5,5,3,5,5,4,5,5,5,3,5,5,4,5,5,5,5,3,3,5,3,4,5,5,5,5,5,5,4,5,5,5,5,5,5,5,5,3,4,4,5,5,5,5,5,3,5,5,4,5,4,4,5,5,5,5,5,5,5,2,3,4,5,5,5,5,3,5,4,4,5,5,3,2,5,5,5,5,3,4,2,2,5,5,5,5,5,4,4,3,2,4,5,3,4,5,4,4,2,5,5,5,3,5,3,3,2,3,5,5,4,5,5,4,5,5,3,5,4,2,3,5,5,5,5,4,4,5,3,2,5,5,5,5,5,5,5,5,3,5,5,5,5,5,2,4,5,4,5,2,5,3,5,4,4,5,3,5,3,5,3,4,5,5,5,4,2,3,5,4,5,5,5,3,5,3,5,4,5,2,5,5,5,4,5,5,5,5,3,3,5,5,5,4,5,5,5,5,5,4,5,5,4,5,5,2,5,5,3,4,4,5,4,5,3,4,5,5,5,5,3,4,5,4,5,2,5,3,5,5,3,5,4,4,4,5,5,5,5,3,3,5,5,4,5,4,5,4,5,3,5,3,4,4,4,5,5,4,4,5,4,5,5,5,5,5,4,5,4,5,4,5,5,5,2,5,5,5,4,5,5,5,5,4,3,5,5,5,4,5,4,5,5,5,3,4,4,5,4,4,4,4,5,5,4,5,5,5,5,3,2,4,5,2,5,5,5,5,5,5,4,5,5,4,5,4,5,3,4,4,5,5,5,2,4,3,5,4,2,5,5,5,4,5,4,5,5,5,3,3,4,4,5,4,3,3,5,4,3,3,3,5,3,5,5,4,5,5,5,3,5,5,5,5,5,5,4,5,5,4,5,5,5,5,3,5,3,5,5,5,4,4,4,5,5,5,3,3,4,5,4,5,5,5,4,5,2,4,2,5,4,5,5,5,4,5,5,5,5,5,2,5,5,3,3,4,4,4,5,5,4,5,5,5,5,5,5,4,3,4,5,4,5,5,5,3,5,4,5,5,5,3,5,4,5,5,3,2,5,5,4,5,5,3,5,3,5,5,2,5,4,4,2,5,3,5,5,5,5,4,5,5,5,3,5,4,5,5,5,5,5,5,5,4,3,5,5,5,2,5,3,5,4,5,5,5,5,4,3,5,4,5,5,3,4,4,5,4,2,3,5,5,2,4,5,5,5,4,3,4,5,4,5,5,5,4,5,3,5,5,5,5,2,4,5,5,5,5,4,5,5,4,3,5,5,5,5,2,4,5,5,4,5,5,4,4,5,5,3,5,4,5,5,4,5,5,5,4,3,2,5,5,5,4,4,3,4,2,5,5,3,4,5,4,5,3,3,4,4,5,4,4,5,4,4,5,4,5,5,5,5,5,4,5,5,3,5,5,5,4,5,4,4,5,4,5,5,4,5,3,5,5,5,4,4,5,4,4,5,3,5,3,4,5,4,4,4,5,4,5,5,3,4,5,4,5,5,5,3,4,4,4,5,2,5,5,4,4,2,5,5,4,4,5,5,5,5,5,5,5,5,3,5,5,5,5,5,3,2,3,5,5,5,3,5,3,5,3,5,5,4,5,5,5,3,3,2,4,5),

x7=c(2,2,5,5,2,5,5,5,5,2,5,4,5,5,4,5,5,5,3,5,2,5,5,4,5,5,4,4,2,5,3,5,3,5,4,3,2,5,5,5,3,4,4,3,5,5,4,5,4,4,2,4,5,5,5,5,5,5,3,2,2,5,5,3,5,5,3,5,5,5,3,5,3,4,5,5,4,5,3,3,5,4,2,5,2,5,5,5,3,3,5,5,4,5,5,4,4,2,3,3,4,5,5,4,5,5,3,4,5,4,5,3,3,5,5,5,5,5,5,5,2,5,5,4,5,5,5,2,5,5,4,4,3,2,5,5,5,4,5,3,4,5,2,5,3,4,5,4,4,4,2,2,5,5,3,2,4,3,3,5,5,5,5,3,5,3,3,3,4,4,5,5,5,5,4,5,5,2,4,4,2,3,4,5,4,4,5,3,5,3,2,4,4,3,5,4,4,3,5,3,4,5,5,5,5,5,4,5,3,5,3,5,3,3,4,4,5,3,5,2,53,4,5,5,4,4,3,2,5,2,5,5,5,5,5,3,5,5,5,5,5,4,5,5,5,5,5,5,4,5,5,54,3,5,4,4,4,5,4,4,5,4,5,5,5,4,5,3,4,2,5,2,4,3,4,5,5,4,4,3,4,5,4,4,2,5,4,3,3,4,5,3,3,4,5,5,5,5,3,3,5,5,4,5,4,5,5,5,3,4,2,4,3,4,4,5,5,4,5,5,4,5,5,5,4,5,5,3,5,4,4,3,3,5,5,4,5,2,5,5,5,5,3,3,5,4,5,4,5,5,5,3,5,3,4,4,5,4,3,3,4,5,5,3,5,4,5,5,3,3,3,5,2,5,5,5,5,5,4,2,3,4,3,5,5,5,4,3,3,5,5,5,2,5,3,5,4,2,5,5,5,3,5,4,5,5,5,3,3,3,5,4,3,3,5,5,5,5,3,3,5,4,5,5,4,3,2,5,3,3,5,4,5,5,4,4,5,5,4,2,5,5,4,3,5,3,5,5,5,4,3,4,3,5,5,5,4,4,5,5,2,5,4,3,5,2,2,2,5,4,3,25,4,2,4,5,5,3,5,4,5,3,5,2,4,5,5,4,4,3,5,5,5,5,5,4,3,3,4,4,4,5,52,5,4,5,5,5,5,5,4,3,3,5,2,5,4,4,5,5,4,5,3,2,5,2,5,3,4,2,5,4,5,5,5,3,3,5,5,5,3,5,3,5,5,4,5,5,5,5,4,4,5,4,5,2,5,3,5,4,5,3,4,5,4,5,4,3,5,5,3,3,4,3,4,2,5,5,5,5,4,5,5,5,5,4,3,3,4,5,5,5,4,5,5,5,55,5,3,3,5,5,5,5,4,3,5,5,2,5,5,5,5,3,4,5,5,4,5,5,4,2,5,5,3,5,3,55,5,5,5,5,3,3,5,5,5,2,5,2,5,3,5,4,5,5,3,5,5,5,4,2,4,5,5,4,4,5,3,4,4,3,5,3,2,4,5,5,5,5,4,5,3,5,4,5,3,4,4,4,3,5,5,5,4,5,5,5,4,4,5,2,3,5,5,5,2,3,5,4,3,4,5,5,5,5,5,5,4,2,5,5,5,3,5,2,3,5,2,3,5,44,3,5,5,2,3,3,5,4,4,2,5,4,5,5,5,5,5,5,5,3,4,2,3,3,5,3,2,25,3,4,5,5,5,5,5,3,3,2,3,5),

x8=c(3,5,5,3,2,3,2,5,5,5,5,4,5,2,4,5,4,4,3,5,5,5,5,2,2,5,5,3,3,5,3,5,4,3,3,4,5,3,5,5,3,3,2,4,3,5,2,5,5,4,2,3,5,5,5,5,3,2,4,2,2,4,5,3,5,5,4,5,5,5,3,5,3,4,5,4,4,5,4,4,5,3,2,3,4,5,5,5,3,4,4,3,2,5,5,5,3,2,5,5,5,5,5,3,5,5,3,2,5,3,5,3,4,4,5,5,5,4,5,5,2,3,5,4,5,5,5,3,5,5,5,5,3,3,5,5,5,4,5,3,2,2,5,5,3,3,5,5,3,5,2,2,3,5,3,3,4,5,3,5,5,3,5,2,5,3,3,3,3,3,5,3,5,5,4,3,5,2,4,5,5,3,3,5,4,3,3,3,5,2,5,3,5,5,5,4,3,5,5,3,2,5,3,53,2,4,5,5,3,3,5,5,3,4,3,5,3,5,3,5,3,4,5,3,5,3,3,2,3,4,5,5,5,5,5,3,5,5,5,5,5,5,5,3,5,5,5,5,5,5,5,5,3,2,5,4,5,5,5,5,4,5,2,5,4,4,5,4,3,4,4,5,2,3,2,4,5,5,3,3,2,5,5,4,4,5,5,4,2,3,4,4,3,5,4,5,5,4,5,3,2,5,3,4,5,3,5,5,5,3,5,4,4,3,3,5,5,4,5,5,3,2,5,4,4,4,5,5,5,5,4,4,5,2,5,3,2,5,3,5,2,4,5,3,3,4,5,5,4,5,3,5,5,5,3,4,4,5,4,4,5,4,5,4,2,5,5,5,5,3,3,4,5,2,5,4,5,5,5,3,5,3,4,5,5,5,5,4,3,4,5,5,5,2,5,3,5,3,4,5,4,5,3,5,4,5,5,5,3,3,4,4,4,3,4,2,5,5,3,4,3,5,4,5,4,4,2,5,5,3,3,5,5,5,5,4,4,5,3,4,3,5,5,4,3,5,5,4,4,4,2,3,3,4,5,4,4,3,4,5,2,5,2,4,3,5,2,4,5,5,5,3,5,5,4,5,4,5,4,3,2,3,5,2,4,4,3,4,5,4,4,3,5,5,5,4,5,4,3,3,4,3,4,5,5,2,5,5,5,4,4,5,5,4,3,3,3,5,5,5,3,5,5,3,5,4,5,5,5,5,3,4,3,5,3,3,5,5,4,5,5,2,5,3,5,4,5,5,4,5,5,5,5,4,3,4,2,5,2,5,3,5,3,5,4,5,5,3,4,5,3,5,5,5,2,4,3,3,3,5,5,5,3,4,5,5,5,4,3,5,4,4,5,5,5,3,5,3,5,5,3,4,3,3,5,3,4,5,4,3,5,3,5,5,5,5,5,3,4,5,5,4,4,5,4,3,5,5,3,5,4,5,5,4,5,5,4,3,3,3,5,5,3,4,3,3,3,4,4,5,3,3,5,4,5,3,3,2,4,3,4,4,5,4,4,4,3,5,2,5,5,5,5,2,5,3,5,3,5,4,5,4,3,3,4,3,5,3,5,3,5,5,5,2,3,5,3,4,5,4,5,3,4,5,4,5,4,5,5,5,5,5,4,4,2,5,5,5,2,4,3,4,5,2,5,5,5,4,3,5,5,5,3,2,4,5,4,5,5,4,5,5,5,5,3,5,5,3,2,2,4,3,5,3,5,4,5,3,4,3,4,5,5,5,3,3,3,4,5))


#inits 
list(c = c(1, 1, 1, 1, 1, 1, 1, 1),  b.x1 = 0, b.x2 = 0, b.x3 = 0, b.x4 = 0, b.x5 = 0, b.x6 = 0, b.x7 = 0, b.x8 = 0) ``` 

Answer 1

The problem is that you've only defined 3 a parameters in your model, but you're using a[k] where k ranges from 1 to 8 in the definition of pi[i,k]. So, you would need to either provide the other 5 a parameters as data or define them in the code.