It's been a while, but if you come back, the issue is that you're running a 64-bit OS with greater than 2GB of RAM. While the core game will still work, Forces of Corruption will not work under those conditions until it is patched.
If you downloaded the game through Steam, update the game through Steam. This should fix that issue.
If you installed from CD, and updated to version 1.1, download the second patch on this page:
DO NOT use these patches if you installed through Steam. They will break the game and you will need to reinstall. Only patch CD installations.
http://www.lucasarts.com/support/update/EAWFOC1_1.htmlThat patch contains the fix for 64-bit systems with more than 2GB of RAM.