I had exactly the same problem after reinstalling DBPro after a fresh Windows 7 install. Could you take two screenshots: one from opening DBPro itself and one from clicking a DBPro file. In my case the blank one was using the old editor and I had to change the Open With option to use EditorNew.exe instead of Editor.exe. At least I think that's what I did - I'll have a quick look to see.
Edit Yes, that's what I had to do. Not sure I had to this time. This image shows what you should see after right-clicking a DBPro file followed by Properties/Open With: