QTR-Quadtone RIP

I have some serious problems with qtr. some of my pics don't print
properly. I'm running qtrgui 2.5.2.1 on ms windows xp with epson R800.
"Invalid tif tags in file" error message always shows up with these
pics. sometimes preview seems to look properly when "fit" box is
checked but printer prints either too large (showing only crop part of
the whole pic) or too small. Sometimes preview is completely distorted
- prints don't come out correct either. 

There is no way to resize these pictures manually by unchecking "fit"
box or by changing the centering values. I had converted  pics from
jpeg to tiff using different software (photoimpact, irfanview, several
others) or from nikon raw (nef) to tiff via capture one. all converted
files showed different problems, but none of them worked at all. 

the most strange thing is that some pics from the same series and
conversion methods work fine while others show this strange things...