Replace the fuse for your taillights in the interior fusebox. I had the same problem before and this is what it was. Turns out that the taillights activation moves the actuator that allows you to shift out of park. If you ever have the center console out someday you can see what holds the shifter in park. I'm pretty sure that is what your problem is. Hope this helps.
EDIT: You said you checked all the fuses so I guess my solution would not work. Unless you didn't check the interior fusebox. In which case, do that. It's under the dash, almost directly above where the clutch pedal would be if you had a manual transmission. There is a black knob that you push on that allows it to swing down for access. The offending fuse is located in fuse slot 24, 15 amp rating. It is the one listed under brake lamps in your owners manual. Hopefully this is your problem. If not, I spent too much time for nothing writing this post.
