Plot is area window rotated in preview

I have drawings that when I try to plot to our 11x17 HP LaserJet 5000, the
preview shows a tall window (portrait) with the plot horizontal and cut off
at the right. I have everything set to what I think is correct (landscape,
papersize, plot area...). The drawing is the typical horizontal rectangle
profile. It will not print correctly either.
If I open a blank file and draw a rectangle and preview the plot, it comes
out perfect with the same settings as above. This leads me to believe
something is wrong with the drawings, but what?
Anyone have an idea of what the problem might be?
Thanks, bg