Great,solved!!
as you suggested making a directory named "imageformats" and moving the file qjpeg4.dll inside it solved the problem.
Now is possible for me to correctly save the pictures. (win 7 64bit version)
thank you so much for you help
Citer:
It seems to works only with XP... why Windows is not compatible with Windows ?

Please, could you try that :
- in the zygrib directory, make a directory named
imageformats- move the file
qjpeg4.dll in this directory
- retry zygrib
It seems to work with Vista, but I can't try it under Windows 7.
Thanks to keep us informed of the result.[/quote]