Hey Claas,
I've checked the Accessibility settings and both Alfred and Script editor wasn't there so I've added them manually.
But the problem still persists.
Here's the screenshot with the error.
My guess is there's something with the path escaping, because the whole path to the workflow is "/Volumes/320GB/Cloud/Resilio Sync/Application Support/Alfred 2/Alfred.alfredpreferences/workflows/user.workflow.1FD14E1C-2721-438B-9A2E-9E449F4D8E88"
I'm on Mac OS X 10.11.6 just in case.
Cheers,
Andrey