[Serusers] SER doesn't create TCP registrations

Hi I'm having some trouble getting SER working. I am using example Hello World example ser.cfg (in Ser-GettingStarted.pdf). My client can REGISTER using UDP successfully, but when I to REGISTER with TCP, it fails. I performed a wireshark trace, and the problem is when the client sends a SYN, SER responds with an RST, so the TCP 3 way handshake doesn't finish. The output of SER shows: Listening on udp: 132.181.9.24 [132.181.9.24]:5060 tcp: 132.181.9.24 [132.181.9.24]:5060 Aliases: tcp: cosc4101.cosc.canterbury.ac.nz:5060 udp: cosc4101.cosc.canterbury.ac.nz:5060 What have I done wrong? Thanks Andrew