[ns] Error in executing infra.tcl file

I have included the following code in infra.tcl file set nf [open out.nam w] $nf namtrace-all $nf I also made necessary changes in the stop(Finish) procedure but when i run the simulation, i got the eeor message. Plz check the attached screenshot for the error message. Anyone plz tell me the re

[ns] Error in executing infra.tcl file

I have included the following code in infra.tcl file set nf [open out.nam w] $nf namtrace-all $nf I also made necessary changes in the stop(Finish) procedure but when i run the simulation, i got the eeor message. Plz check the attached screenshot for the error message. Anyone plz tell me