Border problems with 3800

For some reason, my 3800 Epson has decided to give me uneven borders. When I size the image for 1 inch smaller than the media, I get 1/8 on two borders and 7/8 on the other two, even though the preview shows a centered image.
I have gone through all the various settings on the CS4 and the epson driver, and don't see any opportunity to correct this. ???