how to execute Exe file in system

I have a Gams application<http://interfaces.gams-software.com/doku.php?id=env%3aspawning_gams_from_php> which I want to run it through php code after trying many things finally I found that for running in commmand line I should go to C:\Program Files\GAMS23.7 run a command in commandline for running the application as follows: gams.exe trnsport_php.gms the Gams wil be run successfully in commandline now I wanted to run it in php I added an alias with this path C:\Program Files\GAMS23.7 and then I created my php file in there when I want to exacute it with this code in php: if(system('gams.exe trnsport_php.gms')) echo 'Not Error'; else echo'Error'; it shows me Error and again using this one: if(system('./gams.exe trnsport_php.gms')) echo 'Not Error'; else echo'Error'; has printed again Error I tried exec too but no result I don't know what is wrong here. I read the manual but I coudn't find what's wrong here echo system('dir') will show the files of C:\Program Files\GAMS23.7