Well Sorry but sorting his Music is sooooooo personal, how can one really await help on something like that?

Next Thing is that sorting Music is around 50% of the DJ Job if you can't handle this, then rethink about working as a DJ.

Only advice you will get from me is:

I also work on an external harddrive and my Songs are sorted there in different Folders (Rock, Pop, House,etc...) and as I guess your Software is working like any I saw by now, It let's you browse your System and the different Folders that are on your external HD no???

So where is the issue exactly?