Node detection

Hi
I am using two Xbees to form a simple closed network one is connected to the pc while another is on a circuit (with a microcontroller) designed to send X when a metal comes into range the X's relayed are displayed on the X-CTU terminal(when not in AT mode. But any attempts to send data to the other one from the Com port connected Xbee simply receives no acknowledgement ! even the node discover commmand fails to discover tha node.COuld you please help me out!

Could you also please tell me how does one get to Know the address iof the node from which a particular rf packet was transmitted?

Thanks