Regarding the flickering, I had that happen with the regular FlashChat install, so I am guessing it is not with the integration but FlashChat 6.0.6 itself.
I am guessing it is possibly an issue with Flash and FlashChat.
Some of my members has luck with clearing out the Flash cache (in addition to browser cache and cookies.) But not all.
Check out the Adobe Flash Settings Manager.
http://www.macromedia.com/support/do...manager06.html
(It is amazing how much stuff is kept inside of Flash that most people have no idea that it is there. Most 'privacy cleaners' miss the Flash cache.)