Delay when using asset NAS with Unitiserve

when I use the US with my NDS via nstream all is fine, however when choosing music from asset NAS (hd stuff and stuff I previously ripped to wav files) there is a 30 second delay when selecting on the nstream control?

using virgin superhub,would an Ethernet switch sort it out? 

I am a bit techno daft on the network stuff, all is connected with cat 5e not wireless 

help appreciated