CTD Clue - AppInit_Dll entries?

System: Vista Ultimate 32 on an AMD Athlon 64 dual-core PC; 4 GB Ram; 400 GB hard drive; FSX SP2, ATI Radeon 1650 512MB.I use another piece of software unrelated to flight simming called Sibelius which frequently crashed with the annoying "application stopped working" message. The company posted a fix that took care of that problem - and also took care of the same problem in FSX.It used to be that certain add-ons (notably MadDog 2006 and Wilco Airbus) would not quit FSX cleanly: if I was using them and quit FSX, the application would crash with the "application stopped working" message. No longer since I installed the update.I cannot post the file here and I am not sure if non-users of the software can download it. The file looks for AppInit_DLL files in the registry (whatever those may be) and deletes them. In this case it was a file that had something to do with PGP desktop. The disabled file has had no adverse effect on PGP desktop and FSX is a lot more fun to use.Perhaps someone who knows more about the inner depths of programming can follow up on this clue?