tinymce._addVer is not a function

When I try to add an image I get the window I have attached to this post.
Firebug also reports an error:
tinymce._addVer is not a function
[Break on this error] document.write(' tiny_mce_popup.js (line 108)

I'm using TinyMCE external library version 3.0.6.1.

Any fix on this?