Cool that you've fixed your problem.

Strange that such an old hotfix that will've been long since rolled up into service packs and (should) have been applied at source since Vista, should suddenly reappear in 7. And only for some people.

Even weirder is that registry key does not exist on my machine, but I have never seen the problem. And I run all my scripts via the associations. IF the key was there by default and something was deleting it on afflicted machines, it would make sense. But the need to add it -- only on afflicted machines -- is just downright nonsensical.

There is still something more to this problem to be discovered. The only suspect I have at the moment is Strawberry Perl which I have never installed on this machine, but that is tenuous at best.