I had a similar problem. When I took a look at SDP part of the message, the IP of the proxy was always 127.0.0.1. In mediaproxy.ini, I put:
[MediaProxy] proxyIP = my_IP
and it worked. Now mediaproxy was putting a valid IP on the SDP body.
Felipe -- Master Student - Electrical Engineering Department Computer Engineering and Telecommunications Research Group Universidade Federal de Minas Gerais - Brazil
"For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life." John 3:16