QTR-Quadtone RIP

Fred, it sounds like some corruption in a temp file that's only used by 
QTR. 

I'm far from expert, but a dedicated QTR temp file is apparently what 
QTR driver prints from..it's what we see on the QTR viewer...it's not 
used by the Epson driver, even though you can often, but unreliably 
return to it if you leave and go back to QTR (mine vanishes 
unpredictably, requiring search of HD for the original file... Epson 
driver uses the original file, not that QTR file). What I'm describing 
is accidental learning or superstition, I've not read about it anywhere.

I'd suggest Start>Disc Cleanup if you're using XP, then searching HD for 
the original file when you're in QTR. That will eliminate old, possibly 
corrupted temp files that may be the source of your problem. It'll also 
speed your computer. With my setup it's crucial to regularly do that 
Cleanup when I'm Photoshopping because I run out of C-drive space otherwie.