Gas is overflowing from fill spout
 

When I filled up my tank, I stopped at the first click. After I park it I noticed that gas is coming from around the cap. I replaced the cap with one from the MB dealer. I still have the same problem. Today I drove the car for 30 miles, just to use some of the gas. But when I went to take the cap off, gas started flowing out of the fill spout. Can someone tell me why there is much pressure in the tank that it would cause the gas to overflow, even after I drove it for 30 miles. I know that I did not overfill the tank . Your advice is appreciated. Thank you.

Sounds like your car is producing fuel rather than consuming it. Don't tell Bush or Condi.... you might find a M1 tank in your driveway by morning!

Sounds as though tank isn't venting properly, due to possibly a blocked vent pipe, blocked charcoal canister or bad vent valve.
I would suggest having it looked at ASAP!!!
Don't mess around with a fuel leak!! :)

I have read posts before where there is no vent to the tank and the tank collapses, it literally shrinks. This could be happening to your tank, although the lid should take care of any pressure over the threshold. But seriously if you can't diagnose yourself get it to the dealer and have it checked, I would start with the purge valve, seems like it may not be closing and allowing constant vacuum to the tank for vapor creating a negative pressure in the tank. Good luck!
B