Airport Express sound problem

Just got my 1st Mac. 24 inch. Have Apple TV and an airport express to send music to another room. Have M-Audio AV40 powered speakers and everything seemed to work for a few minutes then the AV40's keep cutting out. Any one have suggestions ? thanks in advance from newbie..

first of all... the volume output of the express is controlled by iTunes volume, so check that,
also make sure the cable is inserted correct.. as well as try connecting all the cables first, then restart the airport, (pull it out of the socket, and put it back in)
also, make sure your sound system is on the right input.

if that all wont work... you have a serious issue