Be aware - after troubleshooting an IE/QuickTime problem I had, I noticed that the AOL X Client installed two old Quicktime 5.0b11 plug-ins in my "Internet Plug-ins" folder, inside the "Library" folder.
It completely screwed up all QuickTime content, along with making IE screwy every now and then. I think that there are some other old files lurking in plug-ins (Shockwave or Flash?) or maybe elsewhere, so if you know of any or find any, reply!
Just to be safe, check both your user/Library/Internet Plug-ins Folder and the /Library/Internet Plug-ins Folder.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20010415064245592