Digital BW, The Print

I need a little help. I am running OS 10.2.8 on a newer G3. I have a 
Epson 7500 with MIS UT-1 inks . I am using QTR. Lately, when I start 
printing a 12x18 Image on a 17x22 piece of paper the Computer will 
Lock up half way through or at the point where it is almost finished. 
Either the pointer will not move and I have to reboot or I get the  
multi language message saying to reboot. What is going on. I'm 
somewhat conversant with OS9, and 10 but I do a great deal of my work 
on Windows. If anyone has an idea what is causing this I'd love
to 
know.
John H