Nothing, yes everyone has the same problem. It is sorting alphabetically on Title rather than filename, so even if you have the track numbers at the front of the filename it still does this. I have logged a Mantis about it, and noticed someone else logging a similar issue. Sorting by track number, or a choice would be the best option, I think. Failing that, you have to create a playlist in the admin site to get the order right.... activity on Mantis seems very low over the last few days.... not sure if that means they are getting ready to release, or just they are really busy with certain issues...