I finally picked up my retail copy of Sins today, but the game refuses to install. The install wizard barely runs a second before I simply get a window saying 'Error' and nothing else. The install completion merely says the game experienced a 'Fatal error during installation' and that I should check my settings. 

My computer hits all of the recommended requirements on the nose and I have successfully played the demo. I'm really not getting any clues as to what the problem is and am very frustrated.

Any help that might point me in the right direction would be greatly appreciated.