Hi,
After some days tracking the reason of log error "unable to read 4 bytes", I detected that it´s being thrown after full backups execution, somehow it´s changing the directory ( ./ and ../ ) permissions at client side for user backuppc home (where is .ssh and .profile folder) .
When permissions for ./ and ../ are fixed manually, backupps runs naturally until next full backup execution changes it.
Any Idea where the cause may be? ...ssh configuration? backuppc parameters?