believe I've figured out how to fix it if it's not working
1)Go to Tools
2)Go to Internet Options
3)In General click on Settings
4)Click on View Objects
5)Remove/Delete the MSN Chat Control(you may have to stop sign out or stop using MSN Messenger or something)
Once you've done all that try and sign in and use the chat again.It worked for me
BTW,I use IE6
Hope this works for you as id did for me and I hope you understand my instructions.
Cheers,
Mr.Fix It