[ddouglass]

Are the files on the new drive exactly as they were on the old one? By that I mean are they in the same folder name they were on the old one?
If anything is the slightest bit different then the path will not be right and the file will not be found.
Rebuild the database but make sure and redo the path to the folder with the KMA files. Delete the existing path in the source location and add the new one. Then rebuild. That will fix the search and add tracks. If there was a difference then the old playlists will not work though because the path information is saved as part of the playlist.

I hope you do not think that upgrading to 4.06 cause the problem with the old drive. From what you are saying is the drive was failing. Even if the drive is full it should have still been able to open if something wasn't wrong with it.