import paddle报错，刚安装完时没问题，import paddle正常，第二次就突然报错了

环境：

win10 64

cuda 10.0

paddlepaddle-gpu==1.8.4.post107

python 3.7.3

pip 19.1.1

报错代码：

import paddle
Traceback (most recent call last):

File "", line 1, in
import paddle

File "D:\anaconda3\lib\site-packages\paddle\__init__.py", line 37, in
import paddle.complex

File "D:\anaconda3\lib\site-packages\paddle\complex\__init__.py", line 15, in
from . import tensor

File "D:\anaconda3\lib\site-packages\paddle\complex\tensor\__init__.py", line 15, in
from . import math

File "D:\anaconda3\lib\site-packages\paddle\complex\tensor\math.py", line 15, in
from paddle.common_ops_import import *

File "D:\anaconda3\lib\site-packages\paddle\common_ops_import.py", line 15, in
from paddle.fluid.layer_helper import LayerHelper

File "D:\anaconda3\lib\site-packages\paddle\fluid\__init__.py", line 35, in
from . import framework

File "D:\anaconda3\lib\site-packages\paddle\fluid\framework.py", line 33, in
from .proto import framework_pb2

ValueError: source code string cannot contain null bytes