I got it working by disabling the VPN on my iPad. I am a little surprised that I did not see this sooner because I typically have VPN enabled. Any secrets for getting JRemote to work with a VPN?
Don't know if this relates to your specific situation, but I've found when streaming movies (not music) away from my home network to JRemote (or MO 4Media), depending on the connection, the additional speed penalty from the VPN has sometimes been a factor, i.e., the issue for me has been whether the connection speed is up to the streaming requirement, rather than a problem with JRemote itself. Consistent with that, it might be useful also to review the video quality and audio transcoding settings in JRemote.