i just tried BOTH trainers again (steam and retail) with no problems with two missions.
if you are having problems it helps if you report:
1) STEAM? RETAIL? PATCHED? WHAT VERSION NUMBER?
2) Crashes when?
3)DX9 or DX10?
4) did you try the troubleshooting guide? you may have something blocking the trainer-
best,
Cal
Steam, patched version 1.0.1948 it crashed during my loaded mission halfway thru and if i activate it it crashes when i click load both. DX10 hope that helps