Using Win 7 here and this happened to me as well. What I did was I chose another location to install instead of choosing the same location where you downloaded Royals (same folder etc.) It successfully worked after that. Try my way
I'm getting this issue now. I moved it to my Documents files, now the installing goes to the end (instead of half way) then error.
I am not so sure why :/ Maybe try to delete all Royals files, reboot your computer, and try to install?