Ì have the same problem. I already tried DirectX buster (Staga's link above), but no go. I had installed the 8.1 beta a loooong time ago, and then went back to 8.0, also a loong time ago, using DirectX buster. Everything was fine for a few months, and now those damn messages, and my rudder doesn't work anymore.
If you go to $$$.microsoft.com/directx, the only version they have available for download is the same (bit comparison on files checks out) 8.0 as I already have.
Obviously, I have greivously violated my license agreement with Microsoft by trying to actually _use_ some of their software. Shame on me.
* * * * * BRING ACES HIGH TO LINUX * * * * *