I own a PowerBook G4 17-inch with Tiger OSX 10.4.2. It is connected to the internet through the ethernet port and uses VPN. Safari and e-mail software work fine, however Software Update is nor working well. Sometimes, after a few seconds, I get a message that my computer is not connected to the internet, sometimes the progress bar remains stuck at the beginning. At other times the progress bar stops at the beginning without doing any searches.I tried to run Software Update both from the Apple Menu and from the System Preferences, always encountering the same problem. Can you help, please?