I'm assuming that you are installing it from the retail CD.  I'm not sure what the problem is, but a way for you to get around using that installer from the disc is to use Impulse to download the game digitally.  Impulse is our game downloader and updater.  It's free and you can get it here (http://impulsedriven.com/).

Once you have installed Impulse, you can register the game and then download and install it from there.

Let us know if you have any trouble, or need more direction.

~C