I don't think any genealogist takes seriously the Greek origin of the name. The link below is a list of Gaelic-speaking Scottish highlanders who settled in Oglethorpe's Georgia colony beginning in 1736, compiled from various records as stated. Note that several are shown as being from "Dorris", Scotland. I can't find any modern town of that name but there is still a Durris, Scotland, that even has a website and I suspect that it is the same place, and likely the origin of the surname Dorris.

http://www.electricscotland.com/history/america/darien.htm

http://www.durris.net/html/durris_-_history.html