Cruzer Blade 64GB via Mac with music not recogised by may car

I checked and it is already formatted to FAT32. When pluged into my aux input in the car it tries to recogie but then stops and shows error

All I did was unpack it, plug it in to my computer (Mac Os10.4.7) copied the files from itunes onto the drive, it all showed up ok.

I now have it plugged into my laptop (Mac os 10.6.8) and it still shows all my files and is recognised.

Sould I have loaded everything on from my laptop instead? 

the default file type of music from iTunes is M4A (AAC) which may not be supported by your car stereo. You may need to convert the files to MP3 before the car stereo can play the files.