I recently installed a new hard disk, moved my user files to it (and set the new location as my home with NetInfo.) I then formatted my old hard disk and installed a new copy of OS X on it.
Now when I try authorizing to the iTunes Music Store in my new OS X installation (via the dialogue that appears when I try playing a Protected AAC file) I get the following message:
There was an error storing your authorization information on this computer.
The required directory was not found or has a permissions error.
I tried deauthorizing but I get the same error. I tried doing the standard repair permissions in Disk Utility, as well as running chown/chmod to ensure all my user files are owned by me and writable by me.
I've seen checked out these two articles but they were not helpful:
http://docs.info.apple.com/article.html?artnum=93035
http://docs.info.apple.com/article.html?artnum=93014
I'd really appreciate any suggestions you have.