Hi,
The file is definitely all right, I can move it via FTP without any issues. The problem is going to be probably on your server side, or the FTP client. Most likely server side – if the permissions or the ownerships were changed (even by accident) on the server side, it will explain the issue.
I strongly recmmend using the plugin installer instead of FTP uploads, it will clean up the directory, refresh the filesystem, set the proper ownerships and permissions and execute the proper activation hooks.