I recommend this:
- Figure out what line is causing error
- Set a breakpoint in firebug in that line, run code again.
- Once execution line is on breakpoint, figure out what "this" is bound to in that context and why it is not jQuery object (I am assuming it should be because this.on is being called). Something must be bind'ing "this" incorrectly. Look for things like bind(), apply(), etc.
Hope that helps.