Fatih C:\Program Files\GAMS23.7 this is where my Gams is. maybe the problem is with permissions what should I do for permissions? what shoud I do to write this path file:'( I need it! when echo system('dir') shows me files of C:\Program Files\GAMS23.7 then it shoud run the command gams.exe transport.gms without giving pathfiles what's wrong here? what reason is here for setting path files? On Fri, Feb 17, 2012 at 5:06 PM, Fatih P. <fatihpiristine@xxxxxxxxx> wrote: > ERRORNULL > maybe program Files which has space should have something like \ which I > don't know ha? > or because of Null It is correct? > > means false.. it cannot find the path. you have problem with path. >