Access to Keychain items is restricted

I recently had to reinstall the OS on my MacBook Pro. I used MobileMe to sync a bunch of my settings back to my computer (including Keychains), and now I can't see any of my Keychain passwords. If I try to view an item and check the "Show password" or "Show note" checkbox, I get a little alert that says "Access to this item is restricted". However, the Access Control tab for that same item has the "Allow all apps access" option selected, with the description saying "Access to this item is not restricted".

Things I've found/tried:

• Keychain First Aid reports no errors with my keychain.
• There is nothing in my ~/Library/Keychains/.syncinfo folder.
• Creating a new default keychain a re-syncing from MobileMe does not fix the issue.

What do I need to do to fix my keychain? I have a bunch of stuff in there (mostly application license keys) that I'd rather not lose.

I know this might sound unrelated but after moving my keychain from one machine to another I've had to fix permissions with Disk Utility in order to regain access to my keychain.

And in my experience it seems to be a bad idea to move your keychain from one machine to another when your password differs between machines.