An ERROR has occurred.

please go to
http://www.mozilla.com/en-US/firefox/new/?from=getfirefox
and download and install the webbrowser. it is free, safe and works fine with chess.com
that may help with most problems, although you still need to clear cache and history occasionally (once a week is good) it certainly will help if you play live chess online here.
Clearing the cache helped.
Why do I keep getting that message when I try to do the Tactics trainer?
Probably because an error has occurred.
Brilliant!!!!!!
Oh, it's more than brilliant. It's brilliantly STUPID!! and I love it!