Tinymce not working in IE from server

Question

I've a Rails application that uses Tinymce to allow users write posts from many forms.

It works perfect in firefox and chrome but it doesn't work in IE. I can assume that but the problem is... it is working perfectly in IE when I try it in my dev enviroment.

When I try to use those forms from server I get these errors:

    SCRIPT438: Object doesn't support this property or method 'parentElement',
tiny_mce.js?1364308119 line 1 character 41026

I know this is not too specific but I hope somebody faced this problem before 8-)

Tinymce version is 3.

Thanks in advance