It looks like this was a false alarm, sorry about that. Once I had finalized the command line arguments I was using for our other programs that weren't crashing, it is now working with those same arguments on the multi-threaded program. Although it is a debug build it also incorporates some optimized (release build) third-party code which is now excluded from the source files, possibly that was the problem.
Cheers
Nigel
Cheers
Nigel
