[Andreas]

Should work.
Are you sure it dies have a valid record?

Btw:
I would implement it as

PHP Code:

function prs_can_moderate()
{
    global $DB_site, $vboptions, $vbphrase, $bbuserinfo, $postownership, $pieceexists, $post;

    return (
        ($bbuserinfo['userid'] == $postownership['userid'])
        OR
        ($bbuserinfo['userid'] == $pieceexists['userid'])
        OR
        ($bbuserinfo['userid'] == $post['userid'])
        OR
        ($bbuserinfo['usergroupid'] == 6)
    ); 


Theoretically this should be faster then ifs.
But maybe PHP is smart enough to optimize this itself?