NFS not sending backups to remote computer.

Hi,
I'm trying to setup sending Proxmox backups to a remote computer, but I receive the following errors:
# pvesm list Backups
Backups:163/vm-163-disk-1.raw raw 107374182400 163
Backups:backup/archive.tar tar 3123701760
Backups:backup/vzdump-qemu-162-2013_11_26-17_15_07.vma.lzo vma.lzo 1239901701
Backups:backup/vzdump-qemu-163-2013_11_26-17_21_17.vma.lzo vma.lzo 2076754804



# /usr/bin/rpcinfo -p IPAddressOfRemoteComputer
rpcinfo: can't contact portmapper: RPC: Remote system error - Connection refused


# rpcinfo -p IPAddressOfRemoteComputer
rpcinfo: can't contact portmapper: RPC: Remote system error - Connection refused


# showmount -e IPAddressOfRemoteComputer
clnt_create: RPC: Port mapper failure - Unable to receive: errno 111 (Connection refused)

Should port mapper be installed? I would have thought if port mapper was needed, then Proxmox would already have port mapper installed.