Thanks,
I have actually found that my circuit was wrong 
when I tried my previous working MIDI out code... I feel stupid for posting before even trying that, sorry... I do receive correct data now, but only for a few seconds, it then becomes erratic again. I thought some bits could be lost during the serial transmission... Has anobody experienced something similar? I'm using a MIDI socket that fits in my breadbord, should I try to solder wires to the legs instead? Could it be more reliable or are there other things to check first?