Naim Unitiserve SSD and Linn Majik

I have a Naim unitiserve SSD connected which saves ripped CDs to a Negear ReadyNAS. The music is played through an Linn Majik DSM. All three products are connected to a Sky router via a network switch.

Most of the time the products work fine, but every so often when I am streaming music to the DSM there is a drop out in sound and I have to reboot the system. I assume the problem has something to do with a connection interruption as the green badge does not usually flash on the front of the unitiserve and the drop out only seems to happen when I am streaming from the unitiserve. The sound seems to drop out briefly for a second or two, come back for a second or two and then drop out totally. On kinksey I get an message saying A problem occurred retrieving content from the specified location and the progress wheel to the left of the play arrow just has lines going round it. 

It’s beginning to get quite annoying as the drop out happens two or three times a day if I am using the system a lot. I have tried to give the unitiserve a permanent ip address, but this doesn’t seem to have solved the problem. Any ideas what my next step should be would be gratefully appreciated.