I am too getting the MAV error. In fact I have been getting that error on the last 2 games I downloaded.
I started to happen when instead of a normal installation we just get an executable which runs the program. No menu location, no desktop icons,.. You need to know how to make shortcuts and put them where you want to run it from.
As for the MAV errors I found a way to get around it. I log off and log back on, then I run the game before I run anything else and it works. I can't play two of them on the same session. If I want to play some other of the three games I need to log off and log on. I don't know if this helps.
People suggest adding it to the list of programs in DEP. You only need to do that if Windows tells you that it has disabled a program because it may not be safe. Adding the program to DEP fixes the problem. One time I had to include iexplorer.exe to the DEP list. A few days later I removed it and iexplorer ran fine.
That's all I have.
-Mario
Wait! people keep posting installation/running/technical problems on the comments page. Use the Forums and you will have a better chance to get real help. This information has been given a dozen times and people still post in the comments page.