drag and drop ad widget locking up

I drug the Custom 250×250 ad widget to the sidebar and placed an AdBrite ad code in ad field. The code is messed up, so I tried to drag the widget back. Every time i do this it locks the page up and I cannot remove the widget. I can drag the other widgets back and forth just fine, but this one is stuck.

Please help.I tried enabling accessibility mode but that didn’t allow me to delete the code. It’s like the code is stuck in the widget somehow.