I have 2 instances of CopSSH (4.4.3) and RSync(5.0.4) installed on Windows 2008(each server replicates to the other). Both periodically fail with the same symptoms. Logs on the Source Server (client) for RSYNC or simple ssh connections to the copssh server merely show "Connection closed by [destination server].
On the destination server (copssh and rsync server) I see Event ID 0 ("The description for Event ID 0 from source sshd cannot be found") in the windows eventlog. In the copssh control panel log I see the connection from the source server ip and then "fatal: seteuid 10000: Operation not permitted"
I have re-installed both copssh and rsync server, and that temporarily fixes the problem. However, within 1 to 10 days it repeats these failures.