It probably depends on your image you have. For this plugin missing some dependencies ( python-difflib, python-requests, python-xmlrpc and unrar)
These dependencies you will have to install it through image. Go to Setup - Software managment - Advanced options- Packed managment
Then try to find dependencies which missing.
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thank you very much, reading your comment i solved subtitles download from Opensubtitles, since dependencie was missing
