I am using iTunes 7.6.2(9) on OSX 10.5.3 with all the updates. The iPhone is native 1.1.3. When I link to iTunes and sync, all goes well except for the Contacts and Calendar. I get a message at the end that reads:
"iTunes could not sync Contacts to the iPhone because Iphone disconnected"

I have reset the phone holding down the home and off buttons. I have also restarted my actual computer.

Can anyone suggest how to fix this issue without upgrading or losing any information on the iPhone. I would like to retain all of my call lists, history, sms conversations, applications, etc.