iPhone 4S as a streaming client

My set-up seems a little flaky (iPeng and Duo). Touching any button on the iPhone (software or hardware) stops playback and quite often the sound will cut out but the track continues to play (according to the time progress in the iPeng). When this happens it's necessary to restart the track. The iTunes library is on the has and my files are in ALAC format which I've restricted to 320kbps playback. I'm streaming wirelessly from the Duo to my phone and then to an airport express so I came to the conclusion that it's probably my set-up that's the problem so I've gone back to streaming using the iTunes remote (with mac on of course) which works very well. I also can't get TuneIn Radio to work at all through iPeng (I have an account and it's set-up in my squeezebox.com). I wonder if anyone has any advice that might help with a mac-less set-up)?