[Serusers] registration to ser server fails

Hello, I am a complete novice to VoIP and am trying to setup SER for the first time...so some of my questions may sound naive. I have installed ser-0.96 on x86 machine running fedora core 9. I followed the getting started guide to start ser using the hello-world.cfg config file. The service starts succesfully: Listening on udp: <ser_ip> [ser_ip]:5060 tcp: <ser_ip> [ser_ip]:5060 where ser_ip is the IP address of the server. I verified that the ser processes are actually running. I then used a UA from ekiga.net to register with the server, but the registration fails - reason: timeout. I dont have any problems pinging the ser_ip. What am I missing? Any help will be appreciated. Thanks, Shri