2005 Audi S4 Question Problem Starting

I recently purchased a 2005 Audi S4. Occaisionly the car will not start for me. The computer reads "Please push in clutch to start car" ; however, the clutch is always pushed in when I am trying. All I hear is a clicking noise coming from the engine, then the error message appears. This will usually take place for a few minutes and many start attempts before the car randomly starts. I have noticed that it happens more often when the car has been sitting in cold weather, or has not been used for over 12-14 hours.