Are you running the touch wireless? When I got mine, I had to upgrade my router to get high res files to work via wireless.
You could also try running the volume at 100% if it's not already-- could be a bit transparency issue.
Maybe put the file you are testing on a USB stick and plug it directly into the touch to eliminate the network issue. Or, if you can hard wire the touch on a temporary basis that would also tell you.
From there, if you have .wav or FLAC files they should pass signal no problem or without any special setup being required. Not sure about other formats but make sure if you have RAR files that you unpack them before playing.