newbie needs help with linux

[miriamr]

sorry for cross posting.
Hi, can anyone help me with this? I installed 2 lan
cards on one box so that with will connect to another
box for backup. I got the two machines pinging each
other using the eth1 but my problem is, I cant
mount a remote folder from the server to the backup
unit.
This is what I want to do,

server A Server B Backup unit
eth0: eth0:
192.168.100.1<---->192.168.100.2
eth1: eth0:
192.168.101.3<---->192.168.101.4
exported folder
/data folder-------> /data

when i try to mount the exported /data on the backup
unit by typing
mount 192.168.101.3:/data /data
It displays
mount:RPC: unable to receive; errno=Connection refused

also when I try typing on the backup unit
rpcinfo -p 192.168.101.3
it says
can't contact portmaper: RPC remote system error -
connection refused

Can you help me please.

[miriamr]

my diagram got garbled heres a clearer picture

serverA ServerB Backup unit
eth0: eth0:
192.168.100.1<---->192.168.100.2
eth1: eth0:
192.168.101.3<---->192.168.101.4
exported folder
/data folder-------> /data