This Javascript code (http://www.kutxa.net/wkn_comun/scripts/saltoSNS.js) doesn't work with an "Undefined Value" error on line 161. The script is executed through the "Entrar" button on this page (http://www.kutxa.net/jkn_home/Home) It works with Mozilla firefox 3.0 beta5. I'm using gtk port of webkit, but It neither works on Windows.
The bug was because of the port for Gtk wasn't implementing new-window thing. Changing to Fixed.