Prepare join failed. Failed to reach erlang port mapper. Timeout connecting to X....

Have two servers I want to join together.

I get the above message, but the timeout is connecting to my Initial machine, not the target.

Host is Windows 7, target is MAC OS X 10.7.3

Have checked and rechecked firewall/ACLs and nothing is blocking the port(s)

I can access the admin page bilaterally.

Any ideas? I'm stumped.