Received message does not have key 'index'

[areslp]

Error messages :

PS D:\work\DeepGTAV-PreSIL-master\DeepGTAV-PreSIL-master\VPilot> python .\dataset
Trying to connect to DeepGTAV
Successfully connected to DeepGTAV
datasetPath : D:\data\object\dataset.pz
Connecting to client...
Message sent to client to begin.
dict_keys(['vehicles', 'peds', 'reward', 'throttle', 'brake', 'steering', 'speed', 'yawRate', 'location', 'time', 'frame'])
received message !
Traceback (most recent call last):
File ".\dataset", line 201, in
index = message['index']
KeyError: 'index'