exit error

I have some VS 2005 C++/cli Win32 apps which are deployed on a Windows 2008 R2 platform. They run there as WoW64 processes and seem fine except for one problem. Intermittently, and for certain users, on exit the apps display a system error that says '<blah blah application> has stopped working. A problem caused the program to stop working correctly. Please close the program', with a 'Close the program' button (notwithstanding that I have closed the program and that seems to have caused the error). This error doesn't happen with the same users with the debug build of the apps, and I have found that even if I link the release builds of the apps with the debug CRT and MFC libraries (which are deployed along with my apps as side-by-side assemblies in my application's directory), the error does not happen either, so it seems to be something specific to the release versions of the CRT and MFC libraries. I have also found that the error is not happening in my application code, it happens after the app's WinMain has exitted. Any suggestions for the cause or for investigating a problem apparently located in the release CRT library code after WinMain has exitted? Thanks. See corresponding event log details below: