Witcher 2, The - Assassins of Kings Cheats
instructions at the bottom and troubleshooting steps also included.
[Edited by Skarrin, 5/28/2011 5:10:14 PM]
You probably have the wrong version of the trainer. The version of the trainer you need is the retail trainer that was released on the 27th of May. I hope this helps you.
And obviously find out what version of the game you have, you can do this by going into the games folder and locating the witcher2.exe file (should be in the bin folder) and right click on it and goto properties, in the new window look for the TAB named details and check it, there you can find the current game version you have, and just match it up with the trainer here.