If you are having issues syncing your phone with iSync (for example, you may experience unexpected disconnections), temporarily disable any third-party software on the phone. The software may be trying to read or write to the same contacts or calendar data as iSync, which can cause the disruption.
Some such applications include PocketTorch AquaCalendar, and Sony Ericsson Desktop (available on Sony Ericsson P900 series phones).
Important: Information about products not manufactured by Apple is provided for information purposes only and does not constitute Apple's recommendation or endorsement. Please contact the vendor for additional information.