Undefined variable problem TinyMce

I encountered this frustrating error when upgrading from v3.x of tinymce to v4. Other people have had the problem but I didn't find a solution posted anywhere.

The problem is simply resolved. Version 4.x does not play well with the advanced theme. Clear out any references to that theme from your init script and the error disappears. I would go so far as to say that when upgrading from v3 to v4 just start again from scratch.