As mentioned by Stefan, channel coding is based on C++ files which are compliled to MEX files. Those files are included in the simulator package for Windows. For other OSs, you have to compile them yourself.
We have a script that does that automatically for you. While being in the main directory of the the simulator, enter
Coding.compileMEX in the command line. This will compile the files. For this to work, a compatible C++ compiler should be available on the system. You can find information about supported compilers here: