gv (gs) not producing full plots on AMD64 with nVidia

[michael <cs@networkingnewsletter.org.uk>]

I'm running Debian etch on my AMD64 box. It has an nVidia GeForce 6600
card and I'm using nVidia's module driver (v169.12). When I try and use
'gv' to display an IDL-produced plot it gives a partial plot, the cursor
shows that interpretting is progressing but it never completes the plot.
(If I take the same file and run it through 'gv' on another machine
there is no problem and the plot is plotted within a second or so.) I'd
welcome ideas on how to diagnose what's happening and on how to fix it.
Thanks, M