function problem with globalising query

[sabret00the]

the call to the function is

PHP Code:

    $pieceexists = $DB_site->query_first("
        SELECT pieceid, userid, styleid ,catid, title, pagetext, dateline
        FROM prs_pieces
        WHERE pieceid = $p
    ");
    
    $modificationperms = prs_can_moderate();
    if (!$modificationperms)
    {
        echo $modificationperms;
        die('you dont have permission');
    }
    unset($modificationperms); 


and the function is

PHP Code:

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

    if ($bbuserinfo['userid'] == $postownership['userid'])
    {
        $canmodit = TRUE;
    }

    if ($bbuserinfo['userid'] == $pieceexists['userid'])
    {
        $canmodit = TRUE;
    }

    if ($bbuserinfo['userid'] == $post['userid'])
    {
        $canmodit = TRUE;
    }

    if ($bbuserinfo['usergroupid'] == 6)
    {
        $canmodit = TRUE;
    }

    return $canmodit;
} 


so why won't it recognise the $pieceexists query?