A little more info has filtered down to me. Ubuntu (Dapper Drake) is the version. Flash is installed.

The problem occures when trying to access a flash chatroom using Firefox. Flash starts to load but hangs firefox at some point during the process.

I thought the problem was due to Adblockplus blocking the flash application, however if addblockplus is disabled and entry to the chatroom is tryed again all that happens is, a scripting error appears. "A script on this page is cousing your computer to run slow do you want to terminate the thread", the only option available is, "yes".