Why doesn't the application have a "star" icon on the left? (Plugins tab)
You may have extracted the file using windows built in extractor, please try a program like WinRAR or 7-zip.
Alternatively the file could be blocked by windows so please try the following steps:
- Delete unzipped folder.
- Right-click archive file.
- Click "properties".
- Click "unblock".
- Re-extract the archive.