Error when executing smush.py

[luflow]

Hello everybody!

I tested smush.py today and after a while of successfull smushing I got the following error:

Traceback (most recent call last):
  File "smush.py", line 246, in <module>
    main()
  File "smush.py", line 212, in main
    smush.process(arg, recursive)
  File "smush.py", line 62, in process
    self.__walk(dir, self.__smush)
  File "smush.py", line 96, in __walk
    callback(nfile)
  File "smush.py", line 54, in __smush
    self.optimisers[key].optimise()
  File "[...]/optimiser/optimiser.py", line 162, in optimise
    self._keep_smallest_file(self.input, output_file_name)
  File "[...]/optimiser/optimiser.py", line 82, in _keep_smallest_file
    output_size = os.path.getsize(output)
  File "/usr/local/Cellar/python/2.7.9/Frameworks/Python.framework/Versions/2.7/lib/python2.7/genericpath.py", line 49, in getsize
    return os.stat(filename).st_size
OSError: [Errno 2] No such file or directory: '/var/folders/3v/618ps6_92q1ff4r_kbf23r9c0000gn/T/tmpWxWh2H-opt.smush'

Is there any solution for this problem? I don't really know what the cause could be for this problem...