systrace generates html failed everytime on my pc win7

[jsonhu]

Outputting Systrace results...
Tracing complete, writing results
Traceback (most recent call last):
File "D:\Sdk\platform-tools\systrace\systrace.py", line 49, in
sys.exit(run_systrace.main())
File "D:\Sdk\platform-tools\systrace\catapult\systrace\systrace\run_systrace.py", line 196, in main
main_impl(sys.argv)
File "D:\Sdk\platform-tools\systrace\catapult\systrace\systrace\run_systrace.py", line 193, in main_impl
controller.OutputSystraceResults(write_json=options.write_json)
File "D:\Sdk\platform-tools\systrace\catapult\systrace\systrace\systrace_runner.py", line 68, in OutputSystraceResults
self._out_filename)
File "D:\Sdk\platform-tools\systrace\catapult\systrace\systrace\output_generator.py", line 98, in GenerateHTMLOutput
html_file.write(_ConvertToHtmlString(result.raw_data))
File "D:\Sdk\platform-tools\systrace\catapult\systrace\systrace\output_generator.py", line 120, in _ConvertToHtmlString
raise ValueError('Invalid trace result format for HTML output')
ValueError: Invalid trace result format for HTML output