Address is not valid...

I have a network set up and I am trying to make a failover cluster.


The parts of the network that are relevant are the SAN drive (10.0.0.10
255.255.255.192)
Two Servers running Win2k8:

Server 1 two paths to SAN drive using (10.0.0.30, 10.0.0.31 -
255.255.255.192)
Teamed Nic to main 'network' 10.0.0.70 - 255.255.255.192

Server 2 two paths to SAN drive using (10.0.0.32, 10.0.0.33 -
255.255.255.192)
Teamed Nic to main 'network' 10.0.0.71 - 255.255.255.192

The servers passed the Cluster test.

When I attempt to make the cluster I assign the IP 10.0.0.72 to the cluster
and give it the name 'Mail' (it's a mail server fail-over cluster).
(It shows: 10.0.0.0/26 and a space for me to type my IP)

I get the response that:

Address 10.0.0.72 is not valid for it's associated network