Strange problem

I've been happily coding away at my game and regularly testing in both release and debug but a couple of days ago my game stopped working in release, I get the 'blah blah blah.exe has encountered a problem and has to close' Windows message. Weirdly it works in release from within Visual C++ and debug works fine from outside.
Its crashing within...

mWorld->getPhysXDriver()->simulate(time);

I'm a bit stuck with this one

Could be a stray or old NxOgre DLL, try deleting them all and copying them over again from a fresh source, otherwise your computer is cursed and needs to be burned - at a stake.

I'll get the matches.

Thanks for replying, I've cleaned, re-compiled and/or replaced all the .dll's and still I'm having the same problem, I'm totally at a loss, why would it work in debug and through Visual express but not on it's own. It may possibly be something to do with collision callbacks, I'll take another look over the weekend I guess, if not I may borrow your matches...

I've obviously messed something up in the code because I've reverted back to a previous revision an it's all ok, now I just need to work out how I messed it up.
I'll put the stake back in the shed for now.