Hoster 5.09 Has been released May 28, 2013

[Roy Dennis]

This is what I would try first:
If your music is on an external drive make sure it's connected.
Open Hoster, from the Tools menu select Songs database/Build Database check down the list of folders is listing all your song file paths.
Then press the rebuild database button.
As it starts the dialog opens will say something like building xx songs of xxxxx amount, note what the of amount is because that is how many songs it's trying to import.

Then see if the same problem occurs as before, try to note how many songs it gets to before closing.
If it builds without a problem the dialog at the end should tell you so or tell you x amount did not and where to look.