First, you just can't "change" the version number, and expect a file to behave like a different one...
However, as I've said in my previous message, the least significant numbers do not count, as long as the first one are 9.1.xxx.
Which is very strange because, from your description of the problem, a crash that happens in the very moment you put the airplane at JFK, is exactly what would happen if you had the 9.0 G3D.DLL. Can you check GLOBAL.DLL as well ?
Does it happen at JFK only, or at other of our airports as well ?