No, they use the perl version of wwwthreads. Rick ported the whole thing to php. As Ian said, Infopop buyed wwwthreads several months ago, renamed it to ubb.threads.
The old perl versions isn't maintained any more.
So with buying ubb.threads you get a advanced and brand new model of wwwthreads. Developed in php and not in perl. Many more feature, more secure, more reliable and easier to use.