I have seen this happen when Picassa is used to store pics. Any re-orientation is not carried forward in some othe programs.
Just a suggestion,
Also, the Organizer may display thumbnails as upright even though the actual photo is rotated.
Check these two things:
1) Open your photo in Photoshop Elements and ensure that it is properly oriented.
2) While the photo is open in Photoshop Elements, ensure that it is no larger than 2500x1875 pixels in size (72 ppi).
So iPhoto shows the photo upgright, Organizer shows the photo upgright, but Premiere shows the photo sideways...when I get home i'll try opening in Photoshop and see...The pixel size is definitely bigger, would that play a factor as well?
That's why I mentioned it.