Exception-Handling crashed in RELEASE app

Hi folks

I've experimented somewhat with exceptions. So I derived a class from CException and wrote
somewhat like:

TRY
{
// Do any job and in case of an error:
THROW(new CMyException);
}
CATCH_ALL(e)
{
// Different things to do depending on the kind of exception we've caught
(1) if(e->IsKindOf(RUNTIME_CLASS(CMyException)))
{
// Do my stuff
}

(2) e->Delete();
}
END_CATCH_ALL

My app is configured to use mfc as .lib (no MFC42.DLL)
Some .LIB s are included in the app but are configured the same way.

The problem is: With the debug version of the programm everything
works fine while the app crashes on (1) and (2) in the release version.

If you know what the problem is please
answer quick!!!!!!!

NOTE: It seems that any of my release builds (I tried another project) crash on exception-handling.
Why?! (If you want I can send you a source example.)

Thanx
Ronny