Update 1.2 asking for serial??

[Kasbe]

So, I bought Amnesia today in a Media Market store in Hungary, where I'm on vacation (the game wasnt sold in Spain, and I refuse to purchase online). Retail version works perfectly fine, just asks me to play with the game disk inside the tray.
Then, I installed patch 1.2. It didnt work. After some searching around, and copying the new files on the redist folder to the main game folder, I've found myself unable to play the game anymore. It now asks me for a "serial number".
...What serial? I didnt receive a serial with the game, I've looked everyone, on the DVD, the manual, the box, and found no trace of this serial number thing.

So... what do I do now? I want to play the Justine expansion but I seem to be unable to update to 1.2.


P.D: I have the game box with me, and the ticket the cashier gave me, in case you want visual proof of me having a legit copy.