iTunes Permission Error Persisting!

[Prodo123]

Hi! Before I start, I want to let you know I already tried repairing permissions, chmod -R 1777, setting permissions manually in Get Info, and resetting Home permissions via OnyX and User Accounts.

I had a recent data mishap, and the backups I had made turned out to be weird so I had to manually copy /Users/ back into the root directory after a fresh install of ML. Ever since, I've been having permission issues. As of now, all but one remains fixed.

I can't seem to do some things related to iTunes accounts, including but not limited to: linking my user account to iTunes; downloading purchased content from the Store; registering the new install; and some other things. It doesn't give a clear error message, but instead with the included screenshot. or some variant thereof.

I've repaired permissions multiple times and double checked iTunes has read/write capabilities to the iTunes folder, yet the issue persists. Does anyone have a clue as to what the problem might be?

 

[Prodo123]

Update and bump

I forgot to mention, my account is an administrator account. I also have access to the root account, which obviously does not encounter this issue.

The issue is getting worse and worse! It's getting to where I can't even back up my phone because I cannot authorize the computer.
I can't enable automatic downloads and updates.
I can't authorize this computer for my iTunes account.
I can't purchase content, even if it's free, from the iTunes Store.
I can't complete a full sync of my iPhone because, again, computer is not authorized.

I, however can:
Open and browse the iTunes Store
Edit preferences and metadata
Play music

Can ANYONE help with this issue? I'll be attaching 4 more screenshots of the error messages, all pretty much saying that there's a permission error somewhere that Repair Permissions is NOT detecting.

 

[Prodo123]

The problem has been fixed for now.

I had to log in as root. I held Alt while opening iTunes, which allowed me to select the iTunes library from my account's home directory. From there, I activated the computer using the root account.

Oddly enough the computer was already authorized. And once this had been done, iTunes, when opened from my user account, no longer encountered permission errors.

But since nothing had changed in the library except maybe the authorization, I'm sure somewhere in the depths of the filesystem there's still a permission error that could come up. Any idea what that might be?