I got this error when I run my codes under LTE environment in ns2.35 please help be to resolve this error. thank you



set ns_ [new Simulator]

set val(x) 8000.00 ;# X dimension of the topography
set val(y) 1000.00;# Y dimension of the topography

# Predefine tracing
set nf [open t-down-th.nam w]
$ns_ namtrace-all $nf
set f [open t-down-th.tr w]
$ns_ trace-all $f
set opt(nn) 5
set val(sc) "speed5.txt"


#set up color flow
$ns_ color 1 Blue

# Define the LTE topology
# UE(i) <--> eNB <--> aGW <--> server
# Other configuration parameters see ~ns/tcl/lib/ns-default.tcl

# step 1: define the nodes, the order is fixed!!


set eNB [$ns_ node];#node id is 0
set aGW [$ns_ node];#node id is 1
set server [$ns_ node];#node id is 2
$eNB set X_ 4000.0
$eNB set Y_ 500.0
$eNB set Z_ 0.0

for { set i 0} {$i<$opt(nn)} {incr i} {
set node_($i) [$ns_ node];#node id is > 2
}

puts "speed.txt"
source $val(sc)

# step 2: define the links to connect the nodes
for { set i 0} {$i<$opt(nn)} {incr i} {
$ns_ simplex-link $node_($i) $eNB 500Mb 2ms LTEQueue/ULAirQueue
$ns_ simplex-link $eNB $node_($i) 1000Mb 2ms LTEQueue/DLAirQueue
}

$ns_ simplex-link $eNB $aGW 5000Mb 10ms LTEQueue/ULS1Queue
$ns_ simplex-link $aGW $eNB 5000Mb 10ms LTEQueue/DLS1Queue


# The bandwidth between aGW and server is not the bottleneck.
$ns_ duplex-link $server $aGW 1Gb 2ms DropTail

# step 3.4 define the background traffic
# no parameters to be configured by FTP
# we can configue TCP and TCPSink parameters here.
set tcp1 [new Agent/TCP/Linux]
$tcp1 set timestamps_ true
$tcp1 set fid_ 1
$ns_ attach-agent $server $tcp1
set sink1 [new Agent/TCPSink/Sack1]
$ns_ attach-agent $node_(1) $sink1
$ns_ connect $sink1 $tcp1
set ftp1 [new Application/FTP]
$ftp1 attach-agent $tcp1
$ftp1 set type_ FTP

set tcp2 [new Agent/TCP/Linux]
$tcp2 set timestamps_ true
$tcp2 set fid_ 1
$ns_ attach-agent $server $tcp2
set sink2 [new Agent/TCPSink/Sack1]
$ns_ attach-agent $node_(2) $sink2
$ns_ connect $sink2 $tcp2
set ftp2 [new Application/FTP]
$ftp2 attach-agent $tcp2
$ftp2 set type_ FTP

set tcp3 [new Agent/TCP/Linux]
$tcp3 set timestamps_ true
$tcp3 set fid_ 1
$ns_ attach-agent $server $tcp3
set sink3 [new Agent/TCPSink/Sack1]
$ns_ attach-agent $node_(3) $sink3
$ns_ connect $sink3 $tcp3
set ftp3 [new Application/FTP]
$ftp3 attach-agent $tcp3
$ftp3 set type_ FTP

set tcp4 [new Agent/TCP/Linux]
$tcp4 set timestamps_ true
$tcp4 set fid_ 1
$ns_ attach-agent $server $tcp4
set sink4 [new Agent/TCPSink/Sack1]
$ns_ attach-agent $node_(4) $sink4
$ns_ connect $sink4 $tcp4
set ftp4 [new Application/FTP]
$ftp4 attach-agent $tcp4
$ftp4 set type_ FTP


#loss module
set loss_module1 [new ErrorModel]
$loss_module1 set rate_ 0.02
$loss_module1 ranvar [new RandomVariable/Uniform]
$loss_module1 drop-target [new Agent/Null]
$ns_ lossmodel $loss_module1 $eNB $node_(1)

set loss_module2 [new ErrorModel]
$loss_module2 set rate_ 0.02
$loss_module2 ranvar [new RandomVariable/Uniform]
$loss_module2 drop-target [new Agent/Null]
$ns_ lossmodel $loss_module2 $eNB $node_(2)

set loss_module3 [new ErrorModel]
$loss_module3 set rate_ 0.02
$loss_module3 ranvar [new RandomVariable/Uniform]
$loss_module3 drop-target [new Agent/Null]
$ns_ lossmodel $loss_module3 $eNB $node_(3)

set loss_module4 [new ErrorModel]
$loss_module4 set rate_ 0.02
$loss_module4 ranvar [new RandomVariable/Uniform]
$loss_module4 drop-target [new Agent/Null]
$ns_ lossmodel $loss_module4 $eNB $node_(4)


set loss_module6 [new ErrorModel]
$loss_module6 set rate_ 0.0002
$loss_module6 ranvar [new RandomVariable/Uniform]
$loss_module6 drop-target [new Agent/Null]
$ns_ lossmodel $loss_module6 $aGW $eNB

set loss_module7 [new ErrorModel]
$loss_module7 set rate_ 0.00002
$loss_module7 ranvar [new RandomVariable/Uniform]
$loss_module7 drop-target [new Agent/Null]
$ns_ lossmodel $loss_module7 $server $aGW

$ns_ at 0 "$tcp1 select_ca bic"
$ns_ at 0 "$tcp2 select_ca bic"
$ns_ at 0 "$tcp3 select_ca bic"
$ns_ at 0 "$tcp4 select_ca bic"

$ns_ at 1.0 "$ftp1 start"
$ns_ at 30 "$ftp1 stop"
$ns_ at 2.0 "$ftp2 start"
$ns_ at 30 "$ftp2 stop"
$ns_ at 3.0 "$ftp3 start"
$ns_ at 30 "$ftp3 stop"
$ns_ at 4.0 "$ftp4 start"
$ns_ at 30 "$ftp4 stop"



# finish tracing
$ns_ at 30 "finish"
proc finish {} {
#global ns_ f log
global ns_ nf f
$ns_ flush-trace
close $f
close $nf
puts "running nam..."
exec nam t-down-th.nam &
exit 0
}

# Finally, start the simulation.
$ns_ run

---------------------------------------------------

error

cmd select_ca bic
cmd select_ca bic
cmd select_ca bic
cmd select_ca bic
ns: _o22 setdest 6999.402400971616 400.000001 0.6:
(_o22 cmd line 1)
invoked from within
"_o22 cmd setdest 6999.402400971616 400.000001 0.6"
invoked from within
"catch "$self cmd $args" ret"
invoked from within
"if [catch "$self cmd $args" ret] {
set cls [$self info class]
global errorInfo
set savedInfo $errorInfo
error "error when calling class $cls: $args" $..."
(procedure "_o22" line 2)
(SplitObject unknown line 2)
invoked from within