I'm facing the same problem here:
"Cannot send command to IO::Socket::INET=GLOB(0x148ae5d0) (unauthenticated or connection failed)"

But I can login to the remote server from the box where I'm running FOP2:

Trying 50.XXX.XXX.29 ...
Connected to rrcs-50-XXX-XXX-29.sw.biz.rr.com (50.XXX.XXX.29 ).
Escape character is '^]'.
Asterisk Call Manager/1.1

Username and password on the remote server are correct and have been put in the .cfg file:
; Dallas
manager_host=50.XXX.XXX.29
manager_port=5038
manager_user=admin
manager_secret=blablabla

What else I have to check ?