How have you set the output number of channels?
Unfortunately, I'm not home to check right now...but I'm pretty sure that I've told it I have a 7.1 system. It will play 4.0 and 5.1 just fine, but 4.1 (i.e., the bootleg DSOTM DVD-A) and 5.0 (lots of other stuff) result in an error message.
The last time I fooled around with it, I found...umm...something that had a drop-down list of formats, I *think* with the ability to configure what got done with each. I wasn't surprised that something as odd as 4.1 wasn't on it, but found it strange that there was no 5.0.
In general, I find JRiver more useful to me for video and Foobar2000 still the champ for audio. Though with either, I find that sometimes attempting to play files from my NAS works just great and other times it's nothing but stuttering unless I copy the files to a local drive. I *shouldn't* have an issue with my network and mostly just want to blame W*nd*ws.
I really wish there was something out there as truly astonishingly great as the Squeezebox and its server but with the addition of multichannel capabilities. I really thought Logitech would eventually get there, but instead they just dropped the entire product line. The community has, to an absolutely astonishing extent, picked up the slack and come out with some wonderful replacement hardware (or rather, software adapted to existing hardware like the Wandboard), most of which includes HDMI. In my dream, that means that some day someone will add multichannel.