Script On Page Crashes Site in IE

[Fairyglass]

We're getting reports that customers using IE are having problems with accessing product pages on our site- they get a message saying a script is causing the browser to run slowly, and the browser becomes unresponsive- the only way to exit is to end the program via Task Manager or restart the PC. The problem doesn't seem to happen all the time, or at all with Chrome or Firefox. I've just managed to recreate it by looking at the page titled "Bird Decorations" but am unsure as to why it's happening. I've checked via Firebug, but am not really sure what I'm looking for! Can anyone throw any light on the problem please?
Site is www.fairygoodies.co.uk
Thanks!

[guccij]

Looks like your Pirobox plug-in is causing the problem to me.

[Fairyglass]

Thanks for the quick reply Jules. This is going to sound odd, but I didn't know we had a Pirobox plugin... time to speak to the developer methinks.