Memory/ PDF Issues

two computers in crisis
one imac 400 with 64 RAM and 96MD
vRAM and one PPC 7200 80 MB RAM
network all mac Imacs and PPC &7200
server PPC 8550/200

each one using netscape messenger
they download PDFs (of various sizes)
once they are downloaded to the desktop
the user tries to print and is always told
they are out of memory the onle way to
print it is to print it in sections.
I have tried increasing the memory on
acrobat reader
tried only having that one program open