[Roy Dennis]

From the Hoster Menu, select Tools/SongsDatabase/Build Database, When in that dialog is the bottom left panel empty ?
If it is empty then you need to use either the Add Folder or Add Folder/Subfolders buttons above the panel to Brows to the folders containing your files, if you choose the Add folder option make sure you open the folder so that you can see the actual files. If your imports were kmh types check that you can see both the original files and the kmh header files in this folder, if all OK press select and it should add the folder to the list of folders as a path name and at the same time build that folder into the database. You should see a window informing you how many files were added to the database. Do this for each folder containing your music files.
If you chose the subfolders option providing you select the top folder in the tree it should find all the relevant folders.

If that panel was not empty and it contains all the file paths select an individual path and see if the right hand panel populates with a list of the tracks, if no tracks show up for that file path then either the file path is wrong or the kmh headers are missing from that folder.

Example of what could cause this is if your files are on an external drive and your drive volume letter changed.

See how you get on with the info I have given you so far.
If you still cant get your database fixed let us know your version of Windows, are your music tracks imported as kmh or kma types and are they on an external drive or on your C drive ?