hi to all I tried to run the instruaction "make depend; make" from your web site to make recompile to pi.cc &pi.h(because i modified these files) and i attached the message with this email that i get after running but my problem till now not solved . please help me to solve my problem (make modified) note : please if i need to add new files .cc & .h with new name to ns2 please can you provide me the steps or instructions to do that. thank you ali m