I tried to uninstall the maple matlab toolbox via Uninstall Maple 17.app. This seem to execute OK, but then when I tried to launch Matlab the app immediately exited. Investigating the console I saw that it was producing an error:
2013-11-12 19:23:22.290 StartMATLAB[494:707] execl("/Applications/MATLAB_R2012a.app/Contents/MacOS/../../bin/matlab", "/Applications/MATLAB_R2012a.app/Contents/MacOS/../../bin/matlab", "-desktop", "-arch=maci64", nil) failed! errno: 13
Upon closer inspection it seems that the matlab file existed but it's permissions were not setup for executing. I fixed this by issuing:
sudo chmod a+x /Applications/MATLAB_R2012a.app/Contents/MacOS/../../bin/matlab
My guess is that maple's script tried to replace matlab with a backup but forgot to recent the permissions.