I can't run multicast scripts.

[Tao Yu <taoyu@cs.umass.edu>]

I am a new user of ns. 

I installed the ns-allinone-2.1b3 packet. 
When I tried to run the mcast.tcl, I got the following 
error message:

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 can't run any multicast script in ns-2/tcl/ex and ns-2/tcl/ex/newmcast,
anybody can help me with this? 

Thanks all,

Tao