Sean thanks for your reply. I have taken your advice of not moving param files and I reckon it's not a surprise, but the Tut4 runs smoothly:) However I checked all paths and param content and it seems ok... I tried the same set-up on a different machine and it worked. I leave it like that, still some other work to do of learning ECJ. Thanks for again for your help and in general for your dev/support of ECJ. Regards Calle On 5 December 2010 16:56, Sean Luke <[log in to unmask]> wrote: > Calle, this is really mystifying me -- it works fine here on our machines. > Could you run it like this: > > java ec.Evolve -file c:\temp\tutorial4.params -p print-params=true > > ... and let me know what the output is. It SOUNDS like you have a parameter > file which doesn't have any parameters in it: specifically, ec.params. Any > chance you copied that incorrectly? Moving parameter files around is > strongly discouraged btw, for various reasons. > > Sean