Never mind my above post. Solved it, was some other interaction.
I am using the YOAST SEO plugin in combination with FCKEditor, could be some wierd interaction there.
SyntaxError: invalid quantifier
[Break On This Error]
kwregex = new RegExp( "([-/])("+kw+")([-/])?" );
in the file host/wp-content/plugins/wordpress-seo/js/wp-seo-metabox.js?ver=1.4.13
