[Sebbb]

Not really a bug in the sense it prevents the program from working, but the "ip_online" table uses MysQL "UPDATE"s based on the primary key "ipaddr" (IP address) in function update_whoonline (vb3.php in my case)

This as the side effect to "hide" different users surfing with the same IP (intranet, universities, or... me testing my website with 2 browsers).

There should be a real "unique key" not based on the sole IP.

You can do this this way :
1) DROP the primary key based on "ipaddr".
2) ALTER TABLE pp_iponline ADD PRIMARY KEY (userid,ipaddr)