[ns] Wireless Error Help!

[Yeping Su <su@ee.washington.edu>]

Hi all,

I am using RedHat7.0 and ns-allinone-2.1b7a, and I met some problems with
wireless part:

$ns simple-wireless.tcl
num_nodes is set 2
warning: Please use -channel as shown in tcl/ex/wireless-mitf.tcl
Starting Simulation...
NS EXITING...

and 

$ns wireless1.tcl
num_nodes is set 3
warning: Please use -channel as shown in tcl/ex/wireless-mitf.tcl
Loading connection pattern...
couldn't read file "../mobility/scene/cbr-3-test": no such file or
directory
    while executing
"source.orig ../mobility/scene/cbr-3-test"
    ("uplevel" body line 1)
    invoked from within
"uplevel source.orig $fileName"
    (procedure "source" line 12)
    invoked from within
"source $val(cp)"
    (file "wireless1.tcl" line 121)

Nothing shows up. Things not related to wireless seems fine, what's the
problem here? 

Thanks a bunch!

su