jQuery Error Length Undefined for Rich text editor

Hi!
When I enabled the rich text editor I get this error in the js console:

Uncaught TypeError: Cannot read property ‘length’ of undefined – jquery.js:2

Once I disabled it, and went to plain text, the error was gone. However, I’d really like the rich text editor. Any ideas?

http://wordpress.org/extend/plugins/wp-user-frontend/