QTR-Quadtone RIP

I am printing multiple images on a single sheet of 17x22 paper.  The 
images do not extend to the full length or width of the paper.

If "Scale to Fit" is checked, the resulting percentage defaults to 99% 
and cannot be changed.  However, the printed images are slightly 
smaller than they should be.  For example, a 3" x 4-1/2" image is about 
1/16 inch shorter than the actual input size.

If I uncheck "Scale to Fit" and set the percentage to 100%, I get an 
error message saying the "Image Does Not Fit".  Printing the image, in 
spite of the error message, results in a full 3 x 4-1/2 image.

Why do I get the error message?

I'm printing on an Epson 3800.

Thanks,

Fred