New Music Server Network Help!

Hi, I have just purchased a Cambridge 640H music server and have wirelessly connected it to my home network - it has scanned my iMac (10.4.8) and copied the music files - all fine and dandy - but when I try to get my Mac to access the server I connect and within less than a minute the connection disappears - although if I try to reconnect then the Mac says I am already connected! - If I wait 5 mins I can repeat the process all over ..... I'm guessing there is a setting somewhere that I havn't looked at ..but where and what ....please!