Hello again white_fang, thanks for your time testing and posting results. But I don't see anything in your instructions that stands out to me. Most users have little or no problems with Windows XP, and any that do occur, are not really game killers and can be fixed fairly easily.
I get my end of mission/exit mission CTDs on Windows 7 Ultimate 32-bit. I HAVE to set the compatibility mode on the LB2.EXE to Windows XP (Service Pack 2 or 3) just to get the game to even load without a Windows error. And all any fixes - whether PositiveG's or Phoenix's - do is make the make stable for me, in-game, and don't compensate for the CTDs after I end a mission, either prematurely or naturally.