When I add one arnold light in the scenes,some erro message attack,I can not understand what is wrong?please give me a help,thanks!

Traceback (most recent call last):
File “opdefObject/arnold_light?PythonModule”, line 1, in <module>
File “CUsers/Administrator/htoa/htoa-2.0.0_r240c4dd_houdini-16.0.557/htoa-2.0.0_r240c4dd_houdini-16.0.557/scripts/python\htoa\ipr.py”, line 15, in <module>
import psutil
File “CUsers/Administrator/htoa/htoa-2.0.0_r240c4dd_houdini-16.0.557/htoa-2.0.0_r240c4dd_houdini-16.0.557\python2.7libs\psutil\__init__.py”, line 113, in <module>
from . import _pswindows as _psplatform
File “CUsers/Administrator/htoa/htoa-2.0.0_r240c4dd_houdini-16.0.557/htoa-2.0.0_r240c4dd_houdini-16.0.557\python2.7libs\psutil\_pswindows.py”, line 14, in <module>
from . import _psutil_windows as cext
ImportError: DLL load failed:

Houdini 16.0.600 arnold 2.0.0

I had similar problems, and it was due to environment variables, use Houdini > Help > About Houdini Show Details to check

Thank you!But It was Nothing changed yet…..