LMSI-G35X

I bought the 4F0 051 510 C Aux cable for the AMI system, but when I plug it in and then connect it to the head phone jack of a mp3 player the MMI system says that "your device may not be connected or operating properly". I have the 4F0 051 510 E cable for my ipod and I have no problems with that. Looking for any insight or ideas anyone has. FWIW the AUX cable does not have a label on it so the only reason I say it's the 510C AMI cable is that's what the ebay auction said the cable was. Thanks

tech info:
I'm running SW: C6-HU 46.1.0 0805
HW: C6-HU 6361D2.0
FC SW: 05071AFC6AB320060
FC PS: 0060 FC HW: H01