I would think it depends on what the radio problem is, but I would suspect it has to come from Australia. Our radios were not even USA-ified (its still in right-hand drive config), and it's pretty particular to this car.
If this were only to have happened with one disk, I would say to remove it and clean it. But since it couldn't recognize even how many disks you have, it sounds like an internal problem. On the off chance, if you have not already done this, I'd recommend removing all your disks and trying to replace the exact one it was trying to read at the time it errored with something else. If the radio scans each disk sequentially, and one disk was dirty and the scan hung and bombed out because of that, perhaps one dirty disk may cause the whole thing to bomb out if there were no workarounds programmed in it? I don't know how the radio works, so that may not make sense, but perhaps it is possible.
06 IBM/blue M6 18"