Reposting what jimbosyn asked over in the PowerBook section, as I'm having the same issue on a new MacBook running 10.4.5
I am unable to add an existing keychain file to my MBP. I open keychain access, then click "edit->keychain list". I then click the "+" symbol to add an existing keychain that I added to ~/Library/Keychains/. All of the keychains are greyed out. I cannot add them back. What am I doing wrong?