[Zachery]

Good document markup helps, looks like you were missing a ; on your line 7, I added it, formatted it, and moved the require_once inside of the conditional.

PHP Code:

if (THIS_SCRIPT == 'private')
{
    require_once('./includes/functions_user.php');
    $avid = $pm['fromuserid'];
    if ($avid == $vbulletin->userinfo['userid'])
    {
           $avid = $pm['touserid'];
    }
    $pm[avatarurl] = fetch_avatar_url($avid);
    if (!$pm[avatarurl]) 
    {
        $pm[avatarurl] = $stylevar['imgdir_misc'] . 'images/misc/unknown.gif';
    } 
    else
    {
       $pm[avatarurl] = $vbulletin->options['bburl'] . '/' . $pm[avatarurl][0];
    }
}