RE: OBD-II code P0128 and P0101
This may sound crazy but did you buy this MAF from a MB dealer wrapped in a blue box or did you find this for cheaper on the internet somewhere? Cleaning the MAF won't help a P101 error, it's gone. Many people have gotten tricked on ebay where a seller has clone MAF's that don't work. They are silk screen with the correct part number but are duds. Like Richard said, it may just be the connector, try spraying electronic cleaner in the connector, make sure it's good. Also, if you OBD2 scanner allows, get some readings at idle and at different RPMs and match it up with someone with the same motor and see how far out of range it is.
The P0128 I got a long time ago on my 2002 C230 and it was the thermostat, especially this time of year. What would happen is the thermostat would stick open and it would take longer than the ECU expected to warm up and throw the code.