I Am Trying To Boost The Framerate Of A Video And Mugui Is Not Working Properly.

I am trying to double the framerate using interpolation to make a video look nice and smooth, and I am following this guide: (http://www.spirton.com/convert-videos-to-60fps/).

I have found a few errors along the way however. The first being that when I try to update MEgui, when it reboots it says cannot run updater.

The second problem is that when I download MKV Toolkit and try to run the file listed in the guide (mkvmerge GUI), it is not on my computer, the file in that location is called MKVToolNix GUI.

The third and the major problem (as it is the one that I can't get past) is that when I try to add a video file to MEgui (step 9), MEgui shows an error when trying to open the file. The error can be seen (https://imgur.com/a/24obM7N) (it's the first picture), and then after clicking okay on that error there is nothing in the input file box, and after a while MEgui will crash (error is picture 2 (https://imgur.com/a/24obM7N)).

I am not sure how to fix this, it is frustrating. Does anybody know how to fix this?

P.S. I am on Windows 10.