loading music

[andyjw001]

Hello there.
Just bought both my kids the 24d vision for Christmas, iHave tried both of the ways that the instructions suggest ( copy and paste from hard drive to the music section of the archos, and using the sinc part of the windows media player).
But when i go to the music section on the archos, it shows the albums, and the tracks, but when i try to play the tracks it just says invalid file format on the little screen.
It does this on both of the devices, so i am obviously missing something and doing something silly.
Please could someone enlighten me as to whst i am doing wrong.
Thanks.
Andy.