Hi Woody,
I'm sorry you did not try my advice in post
http://www.annoyances.org/exec/forum/winxp/t1164206916#1164218344
There is not a single instance of corrupt file association that I could not fix using
this method.
I even go so far as to manually edit the entries under HKC Root in the Registry.
Anyway it's up to you :)
Good luck.