UPDATE: I went to a mercedes dealer and got it checked out. There were no errors and the mechanic also checked the fuse etc and all seemed fine. It wasnt a full diagnosis but they said that if the problem occurs again I should come back. So what could the problem be if there is no error? He suggested that it could be just a one or two time thing that the brake did not connect in some ways which caused the ASR to go on but it was just an idea.

I also got the voltage checked and it was fine, close to the red but still on the green of the scale. They exchanged the battery though, just in case.

So any new ideas? Today when I was driving there were no problems. Im thinking that since the mechanic in MB said it was ok, and since I had no problems, that I shouldnt push my luck. I might stop driving for the next 2 weeks and then more or less safely drive home to Germany.

Ill keep the tip in mind with regards to driving in 3. I was thinking whether that would change help reduce the risk.