Actually, the problem seems to be because of the CKEditor, see the next threads:

http://cksource.com/forums/viewtopic.php?t=20154
http://cksource.com/forums/viewtopic.php?t=21199

Have you updated to the latest version? it seems to solve that specific problem as confirmed in those links.

Oh and answering your first question, I asked my client and yes, he pasted content from a Word document. Is there a way to filter invalid code?

Thanks for the quick response!

Hi, I'm stumbling upon a problem I've just noticed which makes our pages not XHTML 1.0 Transitional compliant.

When editing a simple paragraph, the next line is inserted

<span _fck_bookmark="1" style="display: none; ">&nbsp;</span></p>

Can somebody please explain why is this being inserted if it's not going to be displayed? I can't find any documentation on the "_fck_bookmark" attribute.

Thanks!