Random playing

Hi
I am using LMS on Win 8. When I select an album to play on my Touch via the IR remote Harmony One, it will play the first track then randomly pick another to play from the same album. If I manually check the next one to play then all fine until the next track is due and that's also a random one.
Why doesn't it play in order?
My songs are named as follows without mp3 tags...
01-Track 01.mp3
02-Track 02.mp3
etc etc