I had dampness on the right side of the carpet in the rear of the car also. It turned out to be a disconnected drain hose for the sun roof. When I placed my hand down into the right rear wheel well (under the fuses), I found the water was 3 or 4 inches deep.

Reconnecting the drain hose solved the problem.

__________________
Rick
_____________________
2005 BMW X5 4.4 (Highland Green - Beige interior)
1978 Porsche 928 (Copper Bronze - Cork interior)