When launching OpenSubtitlesDownload by right clicking on the video file in nautilus and selecting Open with other application->OpenSubtitlesDownload, it fails due to quotation marks in the OpenSubtitlesDownload-gnome.desktop exec line, removing them solves the issue.
When launching OpenSubtitlesDownload by right clicking on the video file in nautilus and selecting Open with other application->OpenSubtitlesDownload, it fails due to quotation marks in the OpenSubtitlesDownload-gnome.desktop exec line, removing them solves the issue.