XML Calabash MacOS gives SLF4J Error when running any xpl

Question

I'm trying to install XML Calabash 1.3.2 on MacOS in order to use XPROC. I installed XML Calabash using brew:

brew install calabash

When I enter the following in the terminal:

calabash --version

It shows me the correct output of version 1.3.2 But, when I try to run any xpl file, I receive the following error:

SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.

I tried to install SLF4J using MacPorts, but no success.

Does somebody know how to fix this?

Thanks a lot