iTunes library file cannot be found.

I have an external Seagate NAS drive that stores all my iTunes music and movies because I ran out of space on my iTunes. I suddenly have a problem where iTunes says "iTunes library file cannot be found."

Things I've done:

1. Deleted my library file

2. Dragged my music back into iTunes (i.e. re-import)

3. Went into to preferences -> advanced to make sure that iTunes was pointing at the /Volumes/john.e.schneider/iTunes/iTunes Music folder.

Everything was looking good except that I received the error message that the library file cannot be found and cannot be saved. When I closed iTunes and re-opened, all my music was missing again.

What am I doing wrong? I had my library in the Seagate NAS drive for more than a year without a problem. All the problems I'm encountering are recent and I didn't change anything!