On Thu, 6 Sep 2007, Javier García wrote: A few questions that may help with diagnosis: If you open the gretl console and do pergm varname do you get the error? Or is it only when you select the periodogram option from the menus? Are you running gretl in Spanish or in English? Do you also get an error if you call for the correlogram of the variable, from the menu? Thanks, Allin Cottrell