I found the correct one: $cmd = 'C:\Progra~1\GAMS23.7\gams.exe'.' '.escapeshellarg('C:\Progra~1\GAMS23.7\trnsport_php.gms').' 2>&1'; $out = `$cmd`; var_dump($out); It will show NULL,so No error and I am sure it is correct because If I change gams.exe to egams.exe it recognizes but It can't run through system so my problem in path file has solved here Thanks to All of you. now I should find some solutions for permissions It doesn't relate to address file if I'm correct On Fri, Feb 17, 2012 at 5:27 PM, Negin Nickparsa <nickparsa@xxxxxxxxx>wrote: > :) > > > On Fri, Feb 17, 2012 at 5:27 PM, Fatih P. <fatihpiristine@xxxxxxxxx>wrote: > >> well then fix it. i m not using editor. >> > >