We've sort of skipped the autor/auktor/auctor word in Swedish – it was common in the 18th century with various different spellings but I don't think anyone uses it today (outside of the specialized meaning it (auktor) has in Biology, for someone who has given a Latin name to something).
well, the -äldra- part is related to the word -older- so that one is understandable. the -fatta- part seems to mean understand, so I guess a writer would be someone who helps you understand? having said that, i actually envision a cartoon detective saying -fact? or fiction? you be the judge!. - it may be odd, but it helps me. and then the -are- part just means -er-, ie someone who does the first part of the word for a living ... teacher in english, lärare in swedish.