When replicating from ESX to ESXi or ESXi to ESX host you experience the above error
The cause of this is that only the ESXi host has a Virtual Appliance assignened to it
When a Virtual appliane is used, a Virtual Appliance is then required on both side of the replication.
Ensure that ESX hosts have Virtuals Appliances when replicating to or form ESXi hosts
A common misconception is that only ESXi hosts need VA's