Quick editor do not works & error message

[postcd]

When editing any post, there is quick editor at first and when i hit Save, it only shows working wheel and does nothing.

When i Go into Advanced editor, and Save post, in redirection page it return an error and post is saved:


Warning: preg_replace() [function.preg-replace]: Compilation failed: lookbehind assertion is not fixed length at offset 223 in [path]/includes/functions_newpost.php on line 247
Redirecting...
The post has been successfully edited. You are now being taken to the post.
Click here if your browser does not automatically redirect you.


functions_newpost.php on line 247, there is:

247 $text = preg_replace($urlSearchArray, $urlReplaceArray, $messagetext);
248 if (strpos($text, "@"))
{
$text = preg_replace($emailSearchArray, $emailReplaceArray, $text);
}

$text = convert_url_to_bbcode_parenreplace($text);

return $prepend . $text;
}


List of vBulletin plugins: http://pastebin.com/LQiNK8J3

Please what can be the cause?

// EDIT: Post is saved thru Advanced editor, but all text is removed permanently!...