dakota:
I have read here how many times you have played with your system files. I can't begin to think what you've inadvertently done to the system. I think it's time you did a clean install and start over. I know that isn't the solution you're looking for, but it's what I would do, if I had your link problems. But before you do re install, if you do, I'd try one last thing. Delete your library preference folder in your home directory and reboot. This will force the OS and Finder to do a first-run and restore all possible corruption of the preference files for the system and many of the apps. Unfortunately, you will lose any Finder, Apps, and Dock settings you had, but if it works, it's better than a re-install. Backup you mailboxes, address books, etc to a safe place first.
BTW You can also create a new clean users account, so when you log into it, you can see if your problems are still there. If they are gone, the problem most likely IS the User Library Prefs.