MyBB Hacks

Hi, in a forum when I edit first postbit and add new image, I have this error:

"You have entered an invalid address. Make sure that there is a message and try again."

I checked everything and I think it is all ok, how can I resolve it? thank you

EDIT: resolved, it was a problem with
<form action="editpost.php?pid={$pid}&​amp;processed=1" method="post" enctype="multipart/form-data" name="input">

Thank you Lee