How To Fix: "The iTunes Library.itl file is locked, on a locked disk, or you do not have write permission for this file."

Question

I can't reopen my iTunes after I have to force quit when it does not respond. I get this message:
"The iTunes Library.itl file is locked, on a locked disk, or you do not have write permission for this file."
I've read to do the solutions. I right clicked on both the iTunes and Music folder and went to info for each. On both the lock at the bottom of the Get Info was locked. All of my users including admin can read and write all files within those folders. They are even a shared folder. I clicked on the lock to unlock it, typed in my admin password, and went to the gear to apply to all files inside. After doing that I keep getting the saved message.
I tried another way that I've found online to move my ituneslibrary folder to the desktop and then open my iTunes. In theory the iTunes is supposed to ask for where the iTunes library is. Once that is prompted you quit iTunes and drag the iTunes Library folder back to the folder from the desktop and reopen iTunes to apprently solve the problem. However, when I move the iTunes Library file to the desktop and try to reopne iTunes the icon just keeps bouncing and when I right click the application does not respond.
This problem is only resolved if I restart/shut down my macbook pro which is a 15-inch Core 2 Duo with intel. It will be 5 years old in December. I currently have Lion and the latest iTunes 10.5. This problem started in late December. 

Answer 1

If you hold down the option key when starting iTunes, it will allow you to select a library or create a new one.
You can create a new one, and then add all of your iTunes music back in by simply dragging the old iTunes music file onto iTunes.
There are more detailed instructions at http://support.apple.com/kb/HT1451#
It will show you how to re-build your iTunes database file.