I ran across a bug in PostScript when calling "print PS to file..." in the
World menu. The .eps file displays fine in ghostscript based interpreters
(MacGS and ghostview) but generates an error message on Adobe postscript
interpreters (HP printer and xpsview on SGI) (error of typecheck on image,
operator of setcolorspace). 

For a fix I commented out all the code in Form>>printPostscript:operator:
using a (true) ifFalse: [    ] block. The code in this method apparently
draws the rounded corners on the windows. With the code commented out all
the windows have square corners, but it prints reliably. I haven't done
much Postscript work for 5 years and I'm not familiar with these
operators, so I can't supply a proper fix.

-Russell