Don't know what's causing the error? It seems to be related to the fix for the terrain type in the Dungeon. Maybe remove it for now, since it's glitching?
It's obviously due to the Inferno patch. The thing is, it's been used for a long time, and such bugs would have been noticed.
Perhaps he has the game installed with the Inferno patch on top of an older version. By the way, it's better to remove script90 with the installer, since the patch is now in a different script. Although, it might not be the issue.
I wrote to pavkur on the VT forum, let's see what happens there.
