[STATSGRASS] kriging, fit.variogram - negative range, S-JTSK

[Tomas Lanczos]

I constructed a variogram for spatial data in S-JTSK, following a 
procedure like here: http://casoilresource.lawr.ucdavis.edu/drupal/node/438

When I am trying to fit a variogram spherical or exponential model I am 
getting an error message about negative range. I have a suspicion that 
it is because in S-JTSK we are using negative vaules for coordinates, 
even I don't see any reason why could it be a problem ... am I right? If 
not, what can be the reason?

Thanks a lot in advance

Tomas