I just installed my alpine on my 528i e39 on Friday... Banged my head against a wall for a couple hrs...

ghead
1st, make sure your wires from the CD changer to the convertor are going the "right" direction... Also, there may be a switch on the actual Changer to specify Ai-Net or M-Bus, typically 1 or 2 switch... I connected and reconnected for an hr, thinking thinking the adapters were bad... All i needed was a flip of a switch...
Hope this helps... Good luck...