I can see your search settings look OK.
Puzzling
You say it happened all of a sudden, can you think of something you were doing prior to it going wrong ?
have you messed with the songs.mdb in access at all ?
If you open the build database dialog, does it appear that all the folders are listed in the bottom left window ?
One thing you could try, go to Tools/Hoster Data Folder.
Close Hoster but keep data folder open.
Look down the list for songs.mdb, rename it songs2.mdb
Under that you may have a Songs_backup.mdb.
Rename that one songs.mdb then restart Hoster see if the results are different.
If no different rename them back as they were before.