Issue: VaultWiki and the attachment system

if (THIS_SCRIPT == 'newattachment' AND IMAGE_SPACE AND $_POST['ajax'] AND !empty($registry->GPC['filedata']))
{
	global $vault;

	if (!$vault->misc['attachuser'])
	{
		global $attachlib;

		$vault->unserialize('vault_namespaces');
		$vault->misc['attachuser'] = $attachlib->userinfo['userid'];

		require_once(DIR . '/vault/class/pager.php');
		$special = new vB_WikiPager($registry);
		$special->filter_namespace_by_permission($registry->options['vault_namespaces'][IMAGE_SPACE]['forumid']);

		if ($vault->misc['filtered_childlist'] AND $postuserid = $registry->db->query_first("
			SELECT acu.userid
			FROM " . TABLE_PREFIX . "filedata AS fd
			INNER JOIN " . TABLE_PREFIX . "attachment AS acu ON (acu.filedataid = fd.filedataid)
			LEFT JOIN " . TABLE_PREFIX . "thread AS thread ON (thread.firstpostid = acu.contentid AND thread.title LIKE acu.filename)
			WHERE acu.filedataid IN (" . implode(',', $registry->GPC['filedata']) . ")
				AND thread.forumid IN (" . implode(',', $vault->misc['filtered_childlist']) . ")
			LIMIT 1
		"))
		{
			global $vbulletin;

			// these aren't references of each other
			$attachlib->userinfo['userid'] = $postuserid['userid'];
			$vbulletin->userinfo['userid'] = $postuserid['userid'];
		}
	}
}

Database error in vBulletin 4.1.3:

Invalid SQL:

                       SELECT fd.filedataid
                       FROM attachment AS acu
                       INNER JOIN filedata AS fd ON (acu.filedataid = fd.filedataid)
                       LEFT JOIN thread AS thread ON (thread.firstpostid = acu.contentid AND thread.title LIKE acu.filename)
                       WHERE acu.filedataid = 8955
                               AND acu.userid = 6879
                               AND thread.forumid IN ()
                       LIMIT 1;

MySQL Error   : You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ')
                       LIMIT 1' at line 7
Error Number  : 1064
Request Date  : Thursday, June 9th 2011 @ 10:42:41 AM
Error Date    : Thursday, June 9th 2011 @ 10:42:41 AM
Script        : http://www.mysite.com/asset.php?fid=8955&uid=6879&d=1306253703
Referrer      : http://www.mysite.com/member-6879-electrosphere11/