On plugging the mp3 player into one of the USB slots on the back of my PC and running dmesg i get the following output...

usb 5-1: new high speed USB device using address 4
usb 5-1: device not accepting address 4, error -71
usb 5-1: new high speed USB device using address 5
usb 5-1: device not accepting address 5, error -71

I dont really have any idea what to do next although no doubt as soon as i post this i will work it out!

Can anyone point out to me whats wrong with the device?

Ooohhh!

Raises hand, "I know, I know!"

Ok sonny what's the answer...

Power down both your Linux box and your Iriver.

Make sure that the Iriver is getting NO power (you MUST perform a cold start...)

Now bring up the Linux box and make sure it's running.

Hook up the Iriver and turn it on "cold". On some MP3 devices this requires pulling the batteries.

Explanation:

The Linux USB subsystem assigns device ID's to the USB device. If the USB device has been powered up before it may be retaining a prior ID assigned under Windows or another computer and refuse to accept the new ID command.

A cold boot normally clears this.

BTW: This was driving me nuts with one of my external USB drivers, same problem, same error...

Well with an iriver MP3 hard disk i cant pull the batteries so i powered down both that and my linux box and unplugged the usb cable.

Booted into mandrake then put the cable in checked dmesg which had nothing about usb devices at the end so i figured the player couldnt be getting any power. Powered the player up and got the same output as before. Im pretty sure im mis-understanding what you're asking me to do which is why this hasnt worked.

The external usb device needs to be powered up from a cold start, while it is connected to the Linux machine.

Otherwise Linux will be unable to assign it an ID number.