W2003-IIS6 ignore safe_mode=0

Hello. I try to execute a batch file by using a php with the fuction system() but I am unable although safe_mode=0. I am using a very simple example.bat that only makes echo hello and an example.php that should call that batch, but system() allways returns -1. These things have been checked. -Users IUSR_xxx, IWAM_xxx and group IIS_WPG have privileges (read and execute) on the directory. -The example.php works in comand line >php example.php -phpifo(); says me that safe_mode is off for sure. Have you any idea? Version of PHP is 4.4.2. Thanks for your help.