I am using ubuntu 13.10, and just installed K3b. When I burn an audio disc from a file, the tracks are in the wrong order. Any ideas?

Odd. Ideas would be:

1 - the files are in the wrong order in the original file.
2 - they are burnt in the "wrong" order in k3b (solution: sort them properly, then burn).
3 - when looking at the burnt CD with Dolphin they are not properly sorted (solution: sort them after name).

Could be any number of things. The more info you give the better quality advice you'll get