PS googling that error leas to a lot of windows related stuff about removable drives. but my Windows set up is fine for everythign exelct this one program !
i read here
http://www.sevenforums.com/hardware-...dr3-error.html
that DR3 refers to 3rd entry in disk management table in windows, In my case that is a RAM drive.(R). my C drive is the 4th entry. I wonder if there's some issue with the Kobo installer being confused by RAM drives. I Don't want to have to dismantle my R drive though - I use it for all browser temp internet files & it's very stable. And it has not caused any other installer to glitch.