Do you get the following error message on the device when trying to sync:

"Failure In order to get data from ACT! on your mobile device you must use the command Resend all data from HHC Desktop and then, sync again"

In order to correct this, you need to resend all data again from the Handheld Contact Desktop application.  This should be installed on the same PC where the ACT! database resides.  It could be on a desktop, laptop or on the main server.

Here are the STEPS to complete the resend.