You should still be able to publicly link someone to a file from GDrive... I have just made a blank doc to test for you - https://docs.google.com/document/d/1UI2LbLI53eSxs79iyCEQD0JeeY9R3HCI6egw9I5j-YU/edit... You should even be able to edit it without signing in... (awaits random pish)
I see it Works greatSorry, the page (or document) you have requested does not exist.
Make sure that you have the correct URL and that the owner of the document hasn't deleted it.