I understand that we here are generally 'rationalist' in our approach to the Quran, but I also can't see how 'dream' can mean anything but 'dream', especially in Joseph's case in Surah 12. Yet I don't see a problem with that.
Dream interpretation is part of the psychological sciences, and not an occult art. Of course there are those who treat the phenomenon superstitiously and try to predict the future with it (which would obviously contravene Quranic teachings), but dreams are nevertheless a means of psychological analysis.
If any Prophet rationally analysed dreams to warn a community of the direction in which they are headed, I don't see anything *occult* about that. To suggest a Prophet could not ever analyse a dream is misleading. Prophets were marked foremost by their intelligence and ability to analyse political/social/economic problems. Today we would say they had the skills of kings/politicians, philosophers, sociologists and economists. So why can they not be psychologists (specialising in collective psychology) whose tools include dream analysis? But of course, I'm open to correction.