[ns] nam error urgent help needed

[Nikheel Kumar]

hi all,

whenever i m running followin simple tcl file:-

#Create a simulator object
set ns [new Simulator]

#Open the nam trace file
set nf [open out.nam w]

$ns namtrace-all
$nf

#Define a 'finish' procedure
proc finish {} {
      global ns nf
      $ns flush-trace
      #Close the trace file
      close $nf
      #Execute nam on the trace file
      exec nam out.nam &
      exit 0
}

# Insert your own code for topology creation
# and agent definitions, etc. here

#Call the finish procedure after 5 seconds simulation time
$ns at 5.0 "finish"

#Run the simulation

$ns run

i got nam error/ message :

bash-3.2$ nam:
[code omitted because of length]
: no event type or button # or keysym
    while executing
"bind Listbox <MouseWheel> {
%W yview scroll [expr {- (%D/120)*4}] units
}"
    invoked from within
"if {[tk windowingsystem] eq "classic" || [tk windowingsystem] eq "aqua"} {
bind Listbox <MouseWheel> {
%W yview scroll [expr {- (%D)}] units
}
bind Li..."

how to solve this problem please tell me as soon as possible

thanx in advance