Butterfly - BlockMesh - docker-machine misspelled or could not be found

Hey Everyone,
i installed blue cfd 2017-2 and afterwards Butterfly. when using it everything seams to work until i used the block mesh or snappy hex mesh. After reading blue cfd 2017-1 works better i uninstalled everything and reinstalled it with the older version still leading to the same problem:

image
i recived following error (first sentence translatet):

_Runtime error (IOException): The command ‘docker-machine’ is either misspelled or could not be found.

Traceback:
line 100, in getShellinit, “C:\Users\jpete\AppData\Roaming\McNeel\Rhinoceros\8.0\scripts\butterfly\runmanager.py”
line 112, in getContainerId, “C:\Users\jpete\AppData\Roaming\McNeel\Rhinoceros\8.0\scripts\butterfly\runmanager.py”
line 69, in containerId, “C:\Users\jpete\AppData\Roaming\McNeel\Rhinoceros\8.0\scripts\butterfly\runmanager.py”
line 260, in RunManager__command, “C:\Users\jpete\AppData\Roaming\McNeel\Rhinoceros\8.0\scripts\butterfly\runmanager.py”
line 215, in command, “C:\Users\jpete\AppData\Roaming\McNeel\Rhinoceros\8.0\scripts\butterfly\runmanager.py”
line 316, in run, “C:\Users\jpete\AppData\Roaming\McNeel\Rhinoceros\8.0\scripts\butterfly\runmanager.py”
line 716, in command, “C:\Users\jpete\AppData\Roaming\McNeel\Rhinoceros\8.0\scripts\butterfly\case.py”
line 815, in snappyHexMesh, “C:\Users\jpete\AppData\Roaming\McNeel\Rhinoceros\8.0\scripts\butterfly\case.py”
line 102, in script

I have no idea how to solve this and would highly appreciate any help - many thanks in advance!