[Dovecot] Replication fails with "Remote dsync doesn't use compatible protocol"

I can't get replication to work in Dovecot 2.2.1. I'm getting the following error on the machine where I'm initiating the replication:

richatwork dovecot: doveadm: Error: dsync-remote(richatwork): Error: dsync(local): Remote dsync doesn't use compatible protocol

Both the local and remote servers are running identical versions of Dovecot (2.2.1), so I don't understand why I would be having any sort of "compatible protocol" problem. Any ideas?

I posted the "dovecot -n" output for both servers in my earlier e-mail on this issue, which I sent about 24 hours ago (and which I assume was too long for people to be willing to read).

Rich Wales richw@richw.org