MP3 Player protected ?

Ok tried putting mp3's onto my brothers player its nothing special but does the job for him. Has a 512mb flash drive. Now when i tried transferring the mp3's his computer said that the portable disc drive( player ) is copy protected and this must be removed. So i tried doing it through the player but there is no option for this, so i then tried formatting it but it says the same thing. When i tried it on my own computer i could do it just fine. Any idea if it is his computer stopping me accessing it or his player, help would be very much appreciated. Cheers in advance.