After downloading and installing the latest updates for my powerbook G4 yesterday, upon reboot several native mac applications including itunes, address book,and safari give the following error message when I try to open, "The application cannot be opened "NULL" becasue it is either damaged or incomplete". Something to that effect as I am at work. I have tried several reboots to no avail. The updates were itunes, Garageband, and the latest security update. I tried to download the security update separate and reinstall it but It will not let me install it on my local drive. Any help would be apprec iated. Most all of my other apps work like firefox, the office aps, iwork, ilife just fine.