Library cannot be resolved

Question

When I package Scala project using SBT, I face the following problem:

Java HotSpot(TM) 64-Bit Server VM warning: ignoring option MaxPermSize=256m; support was removed in 8.0
[info] Loading project definition from D:\marathon-master\project
Version '20170916T025229' is not fully supported, please update the git tags.
[info] Set current project to marathon (in build file:/D:/marathon-master/)
[info] Constructing RAML model
java.lang.RuntimeException: Library cannot be resolved: D:\marathon-master\docs\docs\rest-api\public\api\appContainer.raml -- D:\marathon-master\docs\docs\rest-api\public\api\v2/types/app.raml [line=6, col=17]
at scala.sys.package$.error(package.scala:27)
...
[error] (marathon/compile:ramlGenerate) Library cannot be resolved: D:\marathon-master\docs\docs\rest-api\public\api\appContainer.raml -- D:\marathon-master\docs\docs\rest-api\public\api\v2/types/app.raml [line=6, col=17]

And the 5-7 lines code in app.raml like that:

   uses:
     appContainer: appContainer.raml
     artifact: artifact.raml

the directory of app.raml and appContainer.raml is "D:\marathon-master\docs\docs\rest-api\public\api\v2/types/" both. So I change 6 line of app.raml like that:

appContainer: v2/types/appContainer.raml

But when I run "sbt package" again, a warning shows up:

Java HotSpot(TM) 64-Bit Server VM warning: ignoring option MaxPermSize=256m; 
support was removed in 8.0
[info] Loading project definition from D:\marathon-master\project
 Version '20170916T025721' is not fully supported, please update the git tags.
[info] Set current project to marathon (in build file:/D:/marathon-master/)
[warn] File D:\marathon-master\docs\docs\rest-api\public\api\v2\types\v2\types\appContainer.raml does not exist (referenced by 
D:\marathon-master\docs\docs\rest-api\public\api\v2\types\app.raml)
[info] Constructing RAML model
java.lang.RuntimeException: Library cannot be resolved: D:\marathon-master\docs\docs\rest-api\public\api\artifact.raml -- D:\marathon-master\docs\docs\rest-api\public\api\v2/types/app.raml [line=7, col=13]
...
[error] (marathon/compile:ramlGenerate) Library cannot be resolved: 
D:\marathon-master\docs\docs\rest-api\public\api\artifact.raml -- D:\marathon-master\docs\docs\rest-api\public\api\v2/types/app.raml [line=7, col=13]

why have this warning? Any idea?