I was running r.thin on 1500x1500 maps and it ran fine.
I will try to work on the map in incoming.
If you want I can also email you the source code for the new version.
Olga
You're very kind. Did you run r.thin in Grass 4.0? If so, then
the eeror message I got must be due to something else... As for
the new code, I'm afraid i've never installed any code myself so
I don't know how to do it.
Martijn