OK, that was a help. I think I know what the problem is now and I'm close (but still not quite there).
The first thing I tried was selecting a Table (clicking a .vpt file). That didn't work, Windows didn't know how to open the file (no association(?). Then I launched VP-Launch-4.exe and double clicked a table there (I didn't think of selecting a table the last time (doh!)). Again, same message, no program associated to .vpt.
btw, if I launch VPinball and select a table (file\open) it works just fine!
OK, so I'm thinking it wasn't setup properly several months ago when I installed it. It's a nice Saturday evening in the air-conditioning, so I decided to completely re-install it. I read your post thoroughly and went to the site, downloaded the files and proceeded to do exactly as they said. (when I installed it before, I put in on a different logical drive and foldername). I have the PC setup as dual-boot, so XP is on my D: drive along with all of the OS. I'm assuming that D: vs. C: doesn't matter, but I used the exact naming conventions and locations for everything else. I did get confused about the \Program Files\Visual Pinball\Tables as opposed to the VPinMAME\Tables (the issue discussed at the bottom of your thread). I tried it the first way and it didn