You have to be logged in to access the article editor - I got the same screen when I tried to access it when I wasn't logged in. I don't believe any other permissions are required to access it.
Articles require approval once they are "published." Graham usually works a little magic touching up the formatting and making things look good.
If you have problems accessing the article editor when you are logged it, that will be a problem that Graham has to fix; I know he's on a business trip out of the country for a few days so it may be a while before he has a chance to fix things if changes are needed.