LinuxQuestions.org - Not able to Create Samba account in Home Directory Machine.

I'm not able to create Samba Account. it is showing the error message as below

Failed to initialise SAM_ACCOUNT for user <username>. Does this user exist in the UNIX password database ?
Failed to modify password entry for user <username>

Unix accounts are created in Corporate Office, which is in US. We had a dedicated link from our office to US office. Now this link has been disconnected & now we have a VPN connection through internet to US Office. there is a firewall on both the sides. While creating samba account i tried to give netstat command & i saw it is trying to make a connection to the Unix Server at US, but the connection is not getting established it is showing SYN_SENT.

The port from the Home directory server trying to connect to the Unix server is connecting using Dynamic port but the Unix server port it is showing as PORTMAP. Network guys are not opening all the ports in the firewall.

Kindly let me know the DESTINATION PORT that the home directory server is trying to connect to Unix Server, so that i can ask my network guys to open that perticular port. So that i can create Samba account to the users.