I think the old CivAssist needs .NET version 1.1. If that is not installed on WeirdoJoker's PC, but is installed on vmxa's, that would be an explanation?
I'm still using Win7, but I think I remember I had some trouble getting .Net 1.1 installed.
Now the strange thing is: I have three machines, one desktop and two laptops. On all three I installed Win7 via the same DVD (iso image) and I used the same .Net 1.1 installer (which I had downloaded together with CivAssist back in 2007 and kept since). On two machines CivAssist works like a charm, just like it used to on XP, but on the third machine it doesn't notice, when Civ3 starts (no icon in the top left corner), doesn't find the Autosaves (always have to load the current autosave manually) and it doesn't seem to find the tile graphics so the "World Map" view remains more or less blank.