You can't cut heads off or slice people in half (note that you can't do this in the US version either until after the Sands)
I think that if your game came on 3CDs, you got the US version and if it came on a DVD, it's the European version.
Or you can open up your registry and check the value of the key
HKEY_LOCAL_MACHINE\Software\Ubisoft\Prince of Persia The Two Thrones\1.00.999|Product Release
It'll be either Retail NA (North America) or Retail EMEA (Europe, Middle East and Africa).
Though it's also possible this has nothing to do with it, and the trainer's just crap
