I can not recreate the problem now on my local test-server, but the problem was that the IP Based Login preferences page did not load.
As far as I remeber, it throwed an error regarding missing argument for mysql_real_escape_string.
The sanitize_variables function didn’t have access to the wpdb object.
That’s why i inserted the line:
global $wpdb;
and then switched the mysql_real_escape_string commands to $wpdb->_real_escape. Using the real_escape method from $wpdb.
When I did that, the error disappeared.
Hope this is of some help to you.
