How can i add sensor using hostname?

Hi Guys,

While am adding the sensor by using host name it will get error , i.e Host not found. This message indicates that the key (name, address, and so on) was not found. Socket Error # 11001 Host not found. (socket error # 11001), Could you please any one help on that ASAP.I need to add the sensor without IP address we don't have static ip address for that so that need to add sensors using Host name.