Jumping </form> tag after submit

I couldn't find an answer to a wierd problem i have with the fckeditor.
We use the form-builder in the editor and when we save the form with all the form-elements in it (text field, select fields, etc) it saves the </form> tag directly under the starting <form> tag, leaving all the form elements outside the form, thus not submitting the desired data.
Does anybody know what causes this, and how I can solve this...

Thanks in advance,