On Fri, 20 Jun 2014 16:48:38 +0100 Patrick O'Callaghan wrote:
AFAIK it's actually an error from rsync (I've seen it in rsnapshot as well, which is also rsync-based). Google for more.
And apparently, what it actually means is: "Hey! I'm trying to talk to an incompatible version of rsync on the other system."
I got it recently trying to copy a very old system's root to a virtual image and I had to download the source rpm for rsync and build the new rsync on the old system.