You can fix this by editing the dochangeusergroups.php script. Line 126 currently has this:

$aquery = "SELECT t1.USER_ID,t4.GROUP_ID FROM {$config['TABLE_PREFIX']}USERS as t1, {$config['TABLE_PREFIX']}USER_GROUPS as t4 WHERE t1.USER_ID <> '1' and t1.USER_ID = t4.USER_ID $removed $aquery";

Change that, to this:

$aquery = "SELECT t1.USER_ID,t4.GROUP_ID FROM {$config['TABLE_PREFIX']}USERS as t1, {$config['TABLE_PREFIX']}USER_GROUPS as t4, {$config['TABLE_PREFIX']}USER_PROFILE as t2 WHERE t1.USER_ID <> '1' and t1.USER_ID = t4.USER_ID and t1.USER_ID = t2.USER_ID $removed $aquery";