In a setup without a Virtual Center component in the vRanger inventory, direct host-credentials must be used to login to the VMware host machine(s). The backup fails with the above error immediately at the "write" phase (about 24% into the backup task).
Since there is no vCenter component defined in the vRanger Inventory setup, the name of the ESXi/vSphere 5 host must be resolveable through DNS/hosts files FROM THE VRANGER MACHINE. In this case, the "DNS and Routing" settings on the host had not been altered from the VMWare default name of "localhost". This is ambiguous (the Repository was an NFS share on a NAS device), and thus the vRanger machine (which proxies all of the backups in ESXi/vSphere 5) could not "find" the vSphere 5 host to initiate the connection to the NFS share. A "real" name must be entered into the "DNS and Routing" section of the host machine's setup, and DNS "A" and "PTR" records MUST be entered (or if not using DNS, hosts file entries on the vRanger machine and the ESXi/vSphere5 host machine) that are valid.
1) Check that the name of the ESXi/vSphere 5 host machine is correct and valid (not "localhost.local", which is the default).
2) Enter the proper name given to the host in DNS so that resolution to/from it can be done from the vRanger machine, and from the ESXi/vSphere 5 hosts.
3) Make sure the name/IPs of the Repository (e.g. if using a NAS or network share, etc.) are also resolveable, both by "A" (forward) and "PTR" (reverse) lookup records.