I have tried uninstalling( then deleting the game folders off the HD) then running the Setup_Factorio_x64_0.12.20.exe file again with no change.
factorio-current.log : http://pastebin.com/gRWSvFH7
factorio-previous.log : http://pastebin.com/CF3mLNBB

Just to point out there is no prototypes folder in lualib after install:
