It's the same Windows 7 x64 (WOW64) bug I reported in November last year (2010) - see the entry in Microsoft Connect.
And the new Windows 7 Service Pack 1 *HASN'T* fixed it! It doesn't only affect Windows 7 though, it goes back all the way to the very first version of x64 Windows - XP 64-bit.
There's no way to workaround this problem in user code. It is a fundamental design flaw in the very first version of 64-bit Windows. This makes it very hard (expensive) for Microsoft to fix - a proper fix requires a redesign of the whole emulation layer of 32-bit apps on 64-bit Windows. Microsoft charges a minimal sum for their OSes (sarcasm), so it's not like they have the resources to work on anything that doesn't affect everyone. It's very likely that Windows 7 will be forever plagued with this bug as it would seem to be easier (cheaper) to start from a clean sheet with Windows 8. Then again, why bother? It's not as if Microsoft has any real competition at all in the x64 OS market - they own more than 80% of the pie!
From the feedback of my previous post, the problem appears more widespread than Microsoft would want to acknowledge - see Discussions about the Boehm Garbage Collector (Boehm GC). Hopefully this bug gets fixed sooner rather than later.
In the meantime, if you want to test it out yourself, you can download this (extract all and run Tester.exe). Usually running it for a few minutes will get it to crash on x64. Give it 30 minutes if it doesn't. If it doesn't crash (i.e. on 32-bit OS), you'll have to kill the app via task manager after you've tested it though (an unrelated bug in the tester application prevents it from shutting down completely - the app will appear closed but the process remains running).
