It looks like something weird is happening during the discovery phase (where upmpdcli is indeed supposed to serve xml files which describe what services are available).
I think that the first thing to try would be to use a "known working" Control Point, like Bubble UPnP on Android (there is a free, slightly restricted version), or plugplayer on iOS, or upplay (
http://www.lesbonscomptes.com/upplay) on Linux or Windows.
If things work with these, then then the Control Point that you are trying to use has a problem. Else, the upmpdcli config on your runeaudio system has one, we can take it further from there.
I am the upmpdcli developper by the way, I am not sure if I'll get email when things are posted here, if you don't see me responding, please ping me at jf at dockes dot org, I'd be glad to help.
