Hi, folks,
This is my first time commenting, but I think I may have found the solution. I also was getting the "GMAXLOC unfound" error, so I edited the env variables, then subsequently got the "unable to launch... [10b]" error, and it has to do with having quotation marks in the variable value.
My GMAXLOC automatically had 'D:\Program Files (x86)\gmax' as its value, if you have this (or similar, but different path), just remove the single quotes and you should be aces. Also, don't forget the last "\" after gmax to complete the path.
Hope this helps
P.S.: I'm running Windows 7 Enterprise 64-bit