I've look through these forums, and spotted lots of people with the same problem, who seem to recieve the same response.
Problem: Gaim cannot connect.
Cause: GTK 2.8.x is on the host system. This is incompatable with Gaim.
Solution: Remove GTK 2.8.x and replace with 2.6.x.
This is not a feasible solution for an application which is meant to be completely independent of the host machine! When using a PC which is not your own, you cannot "simply" remove the existing GTK installation.
I thought that part of the point of having the GTK installation within Gaim was so that it could be used regardless of what GTK was on the existing system, not just if there wasn't _any_ GTK present.