I already was logged in as an administrator. I tried mounting the .dmg file for the Illustrator 16.0.1 update, then opening a terminal window. In the terminal window I typed:
I then entered my password. The same error message appeared as before. It says:
"Update Failed. Updates could not be applied. This patch is not applicable for you. Please check for updates from the Help menu in your product to see a list of latest updates available."
If I try to to check for updates within Illustrator 16.0.0, I am told that no updates are available, which is obviously not the case.