The transmission in the V8 as well as trhe engine is electronically controlled by an ECU. This ECU (ECU=Electronic Control Unit or "Steuergerät" in German) as well as the engine control computer memorizes and stores any faults (such as malfunctioning sensors) encountered during operation. This procedure and the accompanying fault codes can be retreived and are routinely read out when you have routine maintenance done at Audi. Usually, this is done before anything else when there is transmission or engine trouble to narrow down potential causes of the problem.
Scott Mockry has set up his SJM page in order to enable owners to "read" their computers independently of $$$$ Audi garages. On the page linked in my previous post (just click on the underlined part of my post or paste this address into your browser:
http://www.sjmautotechnik.com/trouble_shooting/ecufv8.html ), this "fault code retrieval" process is described in detail.
IMHO, if you have no experience at all with this, I`d suggest to either have somebody with the necessary knowledge have a look at it or bite the bullet and take it to Audi. Retrieving the fault codes is done in a few minutes and does not cost a fortune, if anything.
But in your case, I strongly believe it is a purely little mechanical problem involving this holding bracket below the shifter gate.