Playing backwards?

Hi hope someone can help. I have an IItronics MP3 which I use to listen to spoken word books. I have loaded on a new book to listen to in the right sequence (disc 1 disc 2 etc) but the darn thing plays the discs in the reverse order (ten, nine etc). Once the disc is playing, the tracks are in the right order. The icon on the MP3 is the arrow that is going over on itsdelf and shows N in a black box. Have gone to the menu and choosen Normal in Random setting menu. This has never hapened before so am frustrated and confused...help anyone?