It sounds like you may have installed a patch that was not for your version of the game. The UK and US versions of a game can use different copy "protection."
Since you have the Adventure Company version, the patch you should use is the one on the
***Adventure Company website***.
Try uninstalling the game, deleting the game folder, and reinstalling the game. Then install the patch from the Adventure Company and see if the game will play. If it still doesn't play, you may have to look for a NoCD.