Getting SQl/php error, help plz

[Prophet2002]

This error is occuring when i try to mass prune users.

Database error in vBulletin Control Panel 2.2.7:

Invalid SQL: SELECT userid,username FROM user WHERE userid IN() LIMIT 0
mysql error: You have an error in your SQL syntax near ') LIMIT 0' at line 1

mysql error number: 1064

I tracked this query down in admin/user.php

......
	$users = $DB_site->query("SELECT userid,username FROM user WHERE userid IN($userids) LIMIT $startat,50");
	if ($DB_site->num_rows($users)) {
		while ($user = $DB_site->fetch_array($users)) {
			echo "<p>Updating threads and posts for user: <i>$user[username]</i> ....\n";
			flush();
			$DB_site->query("UPDATE thread SET postuserid=0, postusername='".addslashes($user[username])."' WHERE postuserid=$user[userid]");
			$DB_site->query("UPDATE post SET userid=0, username='".addslashes($user[username])."' WHERE userid=$user[userid]");
			echo "<b>done</b>.</p>\n";
			flush();
.......

I do have alot of hack installed but i uploaded a fresh user.php and still getting the same error
I'm running MySQL 3.23.41 and php 4.2.2 anyone know whats goin on?