My 2009 335i started having these creaks and squeaks especially loud in the rear compartment. After searching - found this thread and a few others with potential solutions.
A couple of folks had great success with WD-40 but others wondered whether it would hurt the rubber because it was a petroleum based product.
So - I hopped on over to the WD-40 FAQ site
(WD-40) to find out if it was safe for use on rubber products. Site said it was fine for use on rubber. Ok. Decided to give it a shot.
Sprayed WD-40 on a paper towel and then just wiped the seals around the door as shown in the pictures, and wiped the seals around the door opening. There was some kind of white powdery substance on the rubber (perhaps leftover residue from previous applications?) the WD-40 covered that all up. Ended up with the seals looking nice and black.
Took the car for a test drive. Absolute silence. All squeaks, creaks gone!! Gone, I tell you. It's been three days now - no squeaks whatsoever.
Took a total of 10 minutes. Already had the WD-40 and the paper towels. So I did not have to go anywhere to get parts. Instant gratification.
Thanks to Robb for posting the pictures. Very, very helpful indeed.