Some of you may be getting type mismatch errors when matlab2fmex tries to compile matlabcallback.f. This is normal. Using this feature is the only way I found to get the real data out of a pointer pointing to something like mxGetPr. The expectation is that the compiled mex file will still work properly.
Turning off mismatch error messages by a compiler option switch in your mexopts.sh seems to be the easiest way to avoid these messages.