Just a reminder, but check the rules
. I edited your post to avoid drama.
With that out of the way, yes, you need to update ffms2 at least, or, better yet, switch to l-smash works for the decoding.
For the sake of simplicity, grab this
and overwrite the ffms2.dll and ffms2.avsi that you will find in your avisynth's plugins folder with the ones in that 7z, then delete the old index file and re-index the video.