Not sure whats up with the pkg installer.
After a few google searches on how to manually install FFmpeg, I stumbled upon Homebrew - a terminal package manager for OSXhttp://brew.sh/index.html
installed via terminal command: /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homeb ... er/install
then ran: brew install ffmpeg --with-tools
Problem solved, and the Export dialog pops up instead of MM asking if I want to download FFmpeg constantly.