So I take it you don't have the software he used? Or do you have it?
If not, then off the top of my head I would say the DOS program was a program called TurboCNC. That would be a software program that interprets the g code instructions and then tells your machine how and were to move. So in other words, the g code is like a list of instructions that is basically a text file and the controller software, TurboCNC, follows those instructions and tells your machine what to do.
A more popular software for this is called Mach3. Or you can get TruboCNC if you want.
The other software, Profilelab, is called CAM software. CAM stands for Computer Aided Manufacturing. Reading up on this particular software it sounds like it has built in CAD too. CAD stands for Computer Aided Design. So this software is called CAD/CAM. Yes, you could use this software, yet, although they have a 3D version, it seems as though this is mostly a 2D software.
For machining musical instruments you'd probably want a more robust CAM software that can do full 3D tool path generation. There are many out there. MasterCam is the leader of the pack, but everyone has their version of CAM software that they like. I prefer VisualMill and VisualTurn, although I haven't touched my CNC stuff in a while so I'm not good person for making a recommendation for good CAM software. MasterCAM will set you back quite a bit. I don't know what the going rate is as of now, but last I heard I think it was around $10,00 US for a single seat.
If you don't have CAD/CAM you'll need software to do 3D CAD. A really good one is Google SketchUp. It's free and it's a good starter 3D software. The best is SolidWorks! Well, according to me, others will have numerous other recommendations.
That should get you started with getting the software you need.
One last thing though. And that is something called the post processor found in CAM software. I bring this up because I had a problem understanding this when I was first starting out. The post processor is a list of instructions that is specific to your machine. It basically tells your CAM software the size of your machine and numerous other specifications which allows your CAM software to generate the g code instructions custom tailored for your machine.
You found the right spot to ask questions! CNCzone has by far the biggest online community of CNC machinists, so ask away!