MDSM Streaming Pauses frquently

I have a MDSM connected via ethernet switch to a WD Mybook LIve 3TB NAS drive. I'm running Asset UPnP from a laptop connected wired to the same network. When streaming I'm getting frequent 'pauses' in the sound, and the Kinsky display shows the 'spinning wheel'. Can anyone suggest what's causing this? It's as if the SW is checking for new content every 10 minutes or so, but I can't see any settings in either the NAS drive or Asset to stop it doing this.
Any help much appreciated, Gary