Are you sure that '1' is a valid avatar ID?
Either way, this is how I grabbed the avatar path in one of my old mods, its was taken almost verbatim from a vbulletin file. Hope it helps.
PHP Code:
if($vbulletin->userinfo['avatarid']!=0){
$av_data=$vbulletin->db->query_first("SELECT * FROM ". TABLE_PREFIX ."avatars where id='".$vbulletin->userinfo['avatarid']."'");
$avpath=$av_data['avatarpath'];
}
else if($vbulletin->userinfo['userid']!=0){
if ($vbulletin->options['usefileavatar'])
{
$avpath = $vbulletin->options['avatarurl'] . '/avatar' . $vbulletin->userinfo['userid'] . '_' . $vbulletin->userinfo['avatarrevision'] . '.gif';
}
else
{
$avdata=$vbulletin->db->query_first("SELECT * FROM ". TABLE_PREFIX ."customavatar where userid='".$vbulletin->userinfo['userid']."'");
$avpath = 'image.php?' . $vbulletin->session->vars['sessionurl'] . 'u=' . $vbulletin->userinfo['userid'] . "&dateline=$avdata[dateline]";
}
}
else{
$avpath="images/noavatar.gif";
}