probably the proxy file mp4 video was not saved for this project or erased. To open the mvp file you need this proxy original or you need to recreate it from your original video file and renamed as the same name as original file and location.
I also note that there is a "&" sign in the filepath. (Kevin & Page Wedding Video). Using special characters in file - and directory names may be problematic to some programs (although I have not tested on MEP).
The difference from failure to success could be if the program internally uses quotes or not in file/path handling.
I suggest as a general precaution to avoid the "&" sign in file- and directory names (can easily be replaced by "and")