invalid command name"Agent/MIHUser/IFMNGMT/MIPV6/Handover/Handover1"

This is my question. My system Ubuntu18.04 and NS-2.35.
How can I solve,please?
Code:num_nodes is set 10
invalid command name "Agent/MIHUser/IFMNGMT/MIPV6/Handover/Handover1"
while executing
"Agent/MIHUser/IFMNGMT/MIPV6/Handover/Handover1 create _o216 "
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 Agent/MIHUser/IFMNGMT/MIPV6/Handover/Handover1"
invoked from within
"set handover [new Agent/MIHUser/IFMNGMT/MIPV6/Handover/Handover1]"
(file "bear2.tcl" line 177)