uwb channel model error

i cant run the following program..being a beginner kindly help me in resolving problm..

http://in.mathworks.com/matlabcentral/fileexchange/6697-uwb-channel-model/content//UWB_Channel_IEEE_802_15_3a/channel_maskcallback3.m

following is the error with above program-

Error using channel_maskcallback3 (line 6) Invalid Simulink object name: