碰到一个问题。用VMM仿真，报错说monitor的main在调用时候尚未定义

各位好：在此求助一个问题
仿真报错如下：
Error-[NOA] Null object access
../testbench/sata_monitor.sv, 40
The object at dereference depth 1 is being used before it was
constructed/allocated.
Please make sure that the object is allocated before using it.

#0 in \sata_monitor::mainat ../testbench/sata_monitor.sv:40
#1 in \vmm_xactor::newat /ware/synopsys/vcs/etc/vmm/vmm.sv:48072
#2 in \sata_env::reset_dutat ../testbench/sata_env.sv:66
#3 in \vmm_env::cfg_dutat /ware/synopsys/vcs/etc/vmm/vmm.sv:47566
#4 in \sata_env::cfg_dutat ../testbench/sata_env.sv:71
#5 in \vmm_env::pre_testat /ware/synopsys/vcs/etc/vmm/vmm.sv:47408
#6 in \vmm_env::runat /ware/synopsys/vcs/etc/vmm/vmm.sv:47371
#7 in unnamed$$_2 at ../testbench/sata_test.sv:20
#8 in sata_test_top.P_sata_test
不知问题在那，monitor在env的build中已经例化。
在线等。

找到问题了，一个channel没定义