PostScript Puzzle

[gareth@vcn.bc.ca (Gareth Jones)]

Can someone explain this to me?

I created a file in a GS desktop program( GraphicWriter III, if it 
matters) and printed it to disk as a PostScript program. I.e. I held down 
Command-F when I clicked the "OK" button in the Print dialogue box. This 
file printed perfectly when I uploaded it to a LaserWriter Plus printer 
from the GS (using LaserBeam 1.1) or from the Mac (using the Apple 
LaserWriter Utility). However, it failed miserably when I downloaded it 
to an Apple brand 600 dpi PostScript printer. This same printer had 
successfully printed other documents that had been created the same way.

The PostScript error reported in the PostScript Log was that there was an 
offending command in the file which was "%% %%". (There was a square box 
between the pairs of exclamation marks).

So questions: are GSes able to print reliably from modern PostScript 
printers (600 dpi or better) at all? Or is it just the "Print to disk and 
upload" method that becomes flaky? With this in mind, has anyone enjoyed 
success taking GS PostScript files to service bureaux for printing? What 
machines work with these files and what do not?

-Gareth