I have a 2005.5 BRM Engine, and got the P2112 "Throttle Actuator Control System - Stuck Closed" also. I gave it two days and it happened more than once so I purchased the following part from a local (Pittsburgh area) dealer:
03G-128-063-Q Flap $300.00
It was the only one I could find between 3 dealerships and it was a special order that they ended up selling me since they could supposedly get another one in 2 days.
One caveat, some of the posts indicate that you need a 5mm allen wrench to remove the bolts. This was not true in my case. I needed an 8mm triple square driver instead, so I also had to buy:
Sunex 9719 Triple Square 8 Pc Bit Socket Set which contains the 8mm triple square driver needed to remove the 3 bolts which hold the regulating flap assembly onto the EGR valve. It also has the 14mm driver needed to remove rear brake calipers, so not a bad deal for $35.00
There was a oily greasy build-up inside my old flap and EGR, and I did some brief cleaning, but didn't feel like removing more parts at this point, so I went ahead and installed the new flap. The entire process only took about 20 minutes and so far, no more MILs.