 <p>Since this specific issue seems to be resolved but it hasn't been addressed in an answer, I'll make the general remark that when trying to debug an error that pops up in the jQuery/jQuery UI/etc files, it's usually not actually an error IN THAT FILE, it's an error in your usage of it that isn't actually breaking until it gets down into jQuery. So you really want to just figure out "what Javascript that I wrote was being run right before that broke?", and start there.</p>