To close out the forum, Chris suggested the following work arounds and the last one was successful for me.

Try going into the source folder and manually compiling this mex file:
W2MHS/RegionGrowing_mex.cpp

Then go to W2MHS/rf_codes and run the MatLab script:
mx_compile_cartree.m

This script should compile the Random Forest code we sue. If this doesn't work try to manually compile this c program in that same folder.
mex -O best_cut_node.cpp GBCR.cpp GBCP.cpp GBCC.cpp
mex mx_eval_cartree.c