PHP to open Command Line and write command

I need PHP to open the command prompt, type a command into it, and run it.

The prompt is located at: C:/WINDOWS/system32/cmd.exe

The command is:

"C:/Program Files/gs/gs8.61/bin/gswin32c.exe" -sDEVICE=jpeg -dNOPAUSE  -dBATCH -sOutputFile="C:/Documents and Settings/Andrey/My Documents/xampp/htdocs/ProjectArchive/albums/edit/pdftmp".substr($filename, 0, strlen($filename)-4).".jpg\" "C:/Documents and Settings/Andrey/My Documents/xampp/htdocs/ProjectArchive/$image"


I am trying:

$cmd = "C:/WINDOWS/system32/cmd.exe \"C:/Program Files/gs/gs8.61/bin/gswin32c.exe\" -sDEVICE=jpeg -dNOPAUSE  -dBATCH -sOutputFile=\"C:/Documents and Settings/Andrey Grigoryev/My Documents/xampp/htdocs/ProjectArchive/albums/edit/pdftmp/".substr($filename, 0, strlen($filename)-4).".jpg\" \"C:/Documents and Settings/Andrey Grigoryev/My Documents/xampp/htdocs/ProjectArchive/$image\"";
exec ($cmd, $output, $retval);

But it returns an error (and does something completely idiotic in addition)

What would be the proper syntax?

Thank you.