Tracks sticking on my NDX

Could do with some help please.

My NDX/Netgear Ready Nas Duo V2 is connected to a BT Home Hub 4. In the last few days some albums are sticking. I have checked all of my connections which are all tight. The problem seems to be either the Nas or the NDX. The music comes on, stops (as does the clock on the fromt panel) for a few seconds then comes back on again.

It doesnt happen with every track or every album.

Any tips/advice would be much appreciated.