It just started yesterday and did it all day yesterday but today it is no longer doing it. It started after I tried to click on the usercp menu from reading Shipwreck's Divinity II review.
If it helps I'm using
Windows 7 Home Premium 64 with Firefox 3.5.7 64 my add-ons are Gmail Notifier, Greasemonkey, Personas, Remove new tab button, Adblock Plus, Forecastfox, FoxyTunes, Gnome Classic, QuickTime, Shockwave flash and Shockwave for Director.