There are three passwords:
1. The Playonline password you created to match the 8 digit mixed letters and numbers POL account code
2. Your Square Enix account username and password. (You can have multiple POL accounts and passwords within the same overall Square Enix account password, as well as different games such as FFXIV under the SE account.)
3. A local Playonline account created when you first logged into POL. This is associated with the Playonline account code and password. This one is local to your computer only - it does not have any bearing on the POL password and SE account name and password you set up online.
If you need to, you can delete your local Playonline account and just make a new one, re-using the POL account code and password you previously set up.
It's very confusing and I wish SE would come up with a simplified login means like they did with XIV, but as long as the PS2 is supported, we're stuck with it.
Edited, Dec 9th 2012 2:41pm by catwho