Script Error - help!?

-I use Firefox and all of the sudden i keep having an issue with a script not working when i go to a certain site. The script appears to be from Meebo - something i have never even heard of or have downloaded. How the hell do i stop this thing from poping up and screwing my computer up? it give the option to "stop script" but when i do, then click on something else on the site...it comes back!



http://www.meebo.com/cim/sandbox.php?lang=en&version=v92_cim_11_10_4&protocol=http%3A&network=gaiaonline#mcim=1637629%2526aad9b89e87ad6f59d3772034bf3c474a&loc=http%3A%2F%2Fwww.gaiaonline.com%2F%3Flogin_success%3D1311117193&dref=http%3A%2F%2Fwww.gaiaonline.com%2Fauth%2Flogin&title=Welcome%20to%20Gaia%20%7C%20Gaia%20Online:29