problem with simple-rtp.tcl

["Randa" <randa@comp.lancs.ac.uk>]

Hi All,
I am running ns-2.1b3 on Redhat Linux 5.1
When I run tcl/ex/simple-rtp.tcl,  I have the following error:

ns: _o3 run-mcast: invalid command name "0"
    while executing
"[$link set ifacein_] set intf_label_"
    (procedure "_o10" line 3)
    (Node get-oif line 3)
    invoked from within
"$self get-oif $link"
    (procedure "_o10" line 5)
    (Node init-outLink line 5)
    invoked from within
"$node init-outLink"
    (procedure "_o3" line 5)
    (Simulator run-mcast line 5)
    invoked from within
"_o3 run-mcast"

I changed the file tcl/lib/ns-lib.tcl to match the Intserv and mcast patches 
and trace.cc patch in teh problems home page and then recompiled ns but I 
still have the same problem. Can anyone help please?

Thank you
Randa
randa@comp.lancs.ac.uk