Ical And Isync Problems


Running a suite of 4 macs via airport. One Imac G4 one powerbook G4 and 2 ibooks 14 and 12 inch G3. All have Tiger 10.4.2 (updated today). The Imac is fine with .mac synced and Ical running. The problem is with the powerbook and the larger ibook (not attempted the smaller ibook yet). I loaded .mac and promptly got an error message - There was a problem with the sync operation - .mac legacy client exited abnormally, when trying to sync. I then noticed that on launching iCal nothing happened other than a couple of bouces of the icon in the dock. This also happened on the powerbook. As I said the Imac is fine but it was the first loaded with .mac. Its irrelevant what ISP i use. Most help files suggest resetting sync which is not illuminated thus not possible. Under advanced no computer shows up when you try and 'register this computer'- just the same error message. all .mac addresses are different.
much appreciate some help!