For the rough idle, I would suggest an inspection of the motor mounts (because of no tach fluctuations) firstly.
For the A/C problem... seems to be a vacuum leak, but I'm unfamiliar with that whole deal. But I think it's vacuum related.
As for when you disconnect the battery and get the CODE on the radio... you should go to the dealer and get the code for yourself for future use! It's a 5 digit code that you punch in and then press SC. Good luck!
2006 E350 w/ 155k miles (Daily Driver)
1993 300E 3.2L Sedan w/ close to about 300k miles
2003 E500 Brilliant Silver (Had 217k miles when totalled!)
1989 300E with 289,000 miles (had for <1 yr while in HI)
03 CLK 500 cabrio (Mom's)
2006 C230k (Dad's)
1999 S420 (Mom's/Dad's)
2000 C230k Sport sedans
2001 CLK320 Cabrio (Mom's)
1995 C280 My First Mercedes-Benz... (155k miles. EXCEPTIONAL AUTOMOBILE. Was Very hard to let go of!)