UCS-5000 Error

I wanted to pre-order new add-on as pre-sales have started, logged to my account through POL, selected VoA pre-sales link given, accepted terms of service and after that POL account verification page. My POL ID was already there, and I entered my POL password, but I recieved UCS-5000 Error. It says;

"ERROR

UCS-5000

Invalid or incomplete information. Please check your PlayOnline ID and password, and try again."

My POL ID is linked to Square Enix ID if this information helps. I can not pre-order add-on atm, is it something wrong am I doing, or is there any trouble with registration server atm? I can log and play game with no problems, everything seems in order. Anyone else facing same problem please post here. Also any solutions would be greatly appreciated. Thank you.

PS: I hate this PlayOnline thing (><)

Random question, humour me.

Is your POL account EU, NA or JP, and, is your POL installation the same?

I ask this because I got that error when I was in the US (I'm from the UK) trying to access my account on the US POL, I could use POL and XI fine, just not the "secure" section. Most likely due to stuff being slightly different in EU version over US.

Other than that, Idk sorry.

Thank you Ihm. I made a little research over net and found out most of this problem caused by version difference. As a matter of fact my account is EU originated and for the easy installation purposes I used to buy an US version of the game (one of those all in one packs) couple of months ago, and which is currently installed at the moment. Now I'm installing EU version of POL and will give a try again. Though even registration works I may have to install whole game EU version once again. I will post again with an edit if my problem solved. Whole world plays under one server, and all use different versions of game, kind of .... I don't know. Policies, companies, trade rights, whatever, I really don't like this, it affects me and my time lost, who will compensate this?

It is stupid, what I did was just installed the EU POL into a second folder and just pop that one open when I needed to touch the secure area, otherwise I just used the US one. Saves having to reinstall the whole of XI anyway. Plus, this wasn't my computer I was using so removing the US one wasn't an option anyway.

Ok I could purchase add-on with EU POL version. Problem solved. As Ihm suggested, I will switch back US POL version and will save the trouble re-installing again. Thank you.