.
.
.

for {set i 0} {$i < $val(nn)} { incr i } {
set xx [expr rand()*200]
set yy [expr rand()*200]
$n($i) set X_ $xx
$n($i) set Y_ $yy
$n($i) set Z_ 0.0
puts "n($i)"
$ns at 0.0 "$n($i) setdest [$n($i) set X_] [$n($i) set Y_] 0.0"
$ns at 0.0 "$n($i) setdest [$n($i) set X_] [$n($i) set Y_] 0.0"


$n(10) set X_ 0.0 #n(10) is Sink node
$n(10) set Y_ 0.0
$n(10) set Z_ 0.0


$ns at 0.1 "$n(10) setdest 200 0 10.0"
$ns at 0.2 "$n(10) setdest 200 200 10.0"
$ns at 0.3 "$n(10) setdest 0 200 10.0"
$ns at 0.4 "$n(10) setdest 0 0 10.0"


after execute of t.tcl file:
ns: _o234 setdest 200 0 10.0:
(_o234 cmd line 1)
invoked from within
"_o234 cmd setdest 200 0 10.0"
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 "_o234" line 2)
(SplitObject unknown line 2)
invoked from within
"_o234 setdest 200 0 10.0"


please help me