[ns] Error when running Tcl script

[Mpiti Lenkoe <MEL30@hermes.cam.ac.uk>]

Hi,
I get the following errors when running the Script on Marc Greis'
Tutorial.The code is in section IV."The First Tcl script".
This happens when I remove the line "exec nam out.nam &" since with this
line I get the error that nam cannot be started.
I would be happy for a prompt help.

(_o34 cmd line 1)
>     invoked from within
> "_o34 cmd reset"
>     invoked from within
> "catch "$self cmd $args" ret"
>     (procedure "_o34" line 2)
>     (SplitObject unknown line 2)
>     invoked from within
> "$a reset"
>     (procedure "_o10" line 5)
>     (Node do-reset line 5)
>     invoked from within
> "$self do-reset$nodetype_"
>     (procedure "_o10" line 4)
>     (Node reset line 4)
>     invoked from within
> "$Node_($nn) reset"
>     (procedure "_o3" line 11)
>     (Simulator run line 11)
>     invoked from within
> "$ns run"
>     (file "example1b.tcl" line 58)
>
Mpiti