It sounds like the firewall is blocking the program.
Port 69 on the IP Office and the Phone Manager PC- TFTP
This is used by the Phone Manager to obtain data from the IP Office such as user name lists and the switch directory. TFTP is also used during the application log on.
Port 50796 on the IP Office - IPO PC Partner
This port is used by Phone Manager and Soft Console applications to establish communication with the IP Office for call signalling, configuration changes, etc.
Port 50799 on the Phone Manager PC - IPO BLF Updates
Used by Phone Manager to receive status updates for internal speed dial icons. These are sent from the IP Office using the 255.255.255.255 broadcast address.
VoIP
iPhone Manager Pro uses ports 1719 and 1720 for H323 Gatekeeper discover and then a range of ports for VoIP. Therefore we can only recommend iPhone Manager Pro operation across a firewall when using VPN to tunnel the connection.
Open these ports and you should be fine.