[ns] help needed in ns-2

[manju iyer]

hai all,

I have an error as following :

invalid command name "Queue/ERED"
    while executing
"Queue/ERED create _o16 "
    invoked from within
"catch "$className create $o $args" msg"
    invoked from within
"if [catch "$className create $o $args" msg] {
if [string match "__FAILED_SHADOW_OBJECT_" $msg] {
delete $o
return ""
}
global errorInfo
error "class $..."
    (procedure "new" line 3)
    invoked from within
"new Queue/$qtype"
    ("default" arm line 3)
    invoked from within
"switch -exact $qtype {
ErrorModule {
if { [llength $args] > 0 } {
set q [eval new $qtype $args]
} else {
set q [new $qtype Fid]
}
}
intserv {
set qtyp..."
    (procedure "_o3" line 14)
    (Simulator simplex-link line 14)
    invoked from within
"_o3 simplex-link _o10 _o13 2Mb 10ms ERED"
    ("eval" body line 1)
    invoked from within
"eval $self simplex-link $n1 $n2 $bw $delay $type $args"
    (procedure "_o3" line 8)
    (Simulator duplex-link line 8)
    invoked from within
"$ns duplex-link $node_(s1) $node_(r1) 2Mb 10ms ERED"
    (file "tritqm.tcl" line 25)

I don't know how to correct this error ..
Please help