Re: Dragon Age Awakening won't start.

Post number 18 on this thread seams to have solved the problem for some. See if it works for you.

More or less it gives direction to Microsofts download webpage for a download that should fix all the backward compability by installing the missing dll files if I understood it completely. Anyhow, check the thread if you want to get a more exact description of what it does.

Good luck.