the plugin is not working so I looked into what I could find
I noticed that these library files are not on my MAC and where not in the download
how do I get these files (are these missing files my problem)
The file you have mentioned is available as part of the FFMPEG library, usually also included when you install VLC.
You can download the FFMPEG files from the following link: https://ffmpeg.org/download.html that should resolve the error.
I hope this is helpful and if you have any other questions please let us know.