Well, I achieved a victory of sorts (my favorite corollary of Murphy's Law is that if you fool with something long enough either you will fix it or break it). I should have realized that if I could ping the other computers on my home network I could also reference them by IP address (thank goodness I use fixed IP addresses on the network rather than DHCP). The solution was to reference the shared folder by the computer's IP address. I could add a Network Place for the shared folder and reference it as \\192.168.1.105\SharedDocs. Now I have no problem running my incompatible application in XP Mode.
I have to say that in some ways XP Mode still isn't quite ready for prime time.
Edited by Bill Pierce, 24 June 2009 - 08:26 AM.