Problem In Flashmedia Server3.0

hi iam new to flash and iam getting problem in .as file. import mx.remoting.NetServices;import mx.remoting.debug.NetDebug;import mx.remoting.Connection;import mx.controls.Alert;NetServices.setDefaultGatewayUrl(_global.gatewayURL);gatewayConnection = NetServices.createGatewayConnection();the value of _global.gatewayURL iam getting but getting undefined in NetServices and gateway connection.i have installed flash media server and flash cs3professional do i need to install something else to importing mx remoting.netservices