Problems with alledged URL in my reply

[Tickleboy_NL]

Hi,
I've just tried for a about ten times to add another reply to a post, but it kept saying I couldn't post because I first had to move any URLs from my reply. But there were no URLs in my message... Eventually I just tried to post one short phrase, without any interpunction or smilies or whatever, but it still said I have a URL in my message and can't post. Why's that?

Help!!

Thanks a lot,
Frank