If you're running PHP scripts through the command line (crontab or via a bash shell), you can get the following output:
localuser@host ~# php myscript.php ... sh: /php: No such file or directory ...
That mostly happens when you have code like this active.
passthru("php other.php"); exec("php other.php"); shell_exec("php other.php"); ...
First thing to check would be if "php" is a registered binary. Run the following as the user that is running your PHP script (hopefully not the root user).
localuser@host ~# which php /usr/bin/php
If you get no response, try to add the full path to the PHP binary into your script.
passthru("/usr/local/php other.php"); exec("/usr/local/php other.php"); shell_exec("/usr/local/php other.php");
If you do get a response, doublecheck if safe_mode is On for the script you are running. With safe_mode on, it will block the execution of other scripts via the passthru() or exec() calls.