Why I encounterd "Error! Undefined variable: m_sequencer"

OVM
1

When I run the ovm_examples-1.1/08-sequences/05-arb , I encountered the vlog Error “Undefined variable: m_sequencer”. Why?
My programming environment is : Windows Server2003 , Questasim 6.4a
I only add the `include “ovm_macros.svh” in the example file head, and revised the compile_questa_sv.f as the following:
-suppress 2223
+incdir+e:/ovm-2.0/src
e:/ovm-2.0/src/ovm_pkg.sv
top.sv
and add a do.tcl file as following:
vlib work
vlog -f compile_questa_sv.f
vsim -suppress 2223 -do vsim.do -c -suppress 3829 top
run

Please give me some advise, Thanks!

2

I found the error cause , which is the following code:
class root_seq extends ovm_sequence #(item);
I mistyped as such:
class root_seq extends ovm_sequencer #(item);
So, the Questasim report “Undefined variable: m_sequencer”. Thanks all of you who viewed my thread.