[ns] how i solve this error"no class variable Mac/NewMac::bandwidth_"

[reza mohammadi]

hello
i design new mac protocol
my new protocol base class inherite from Mac class
 when i use it follow error ocured and i can't test it
"no class variable Mac/NewMac::bandwidth_"
"no class variable Mac/NewMac::delay_"
"no class variable Mac/NewMac::abstract_"
"no class variable Mac/NewMac::full_duplex_mode_"
can any body  help me?
thanks