Executing a python script from within perl

Hi, I'm new to PHP and just installed apache2 with php support. I'm trying to execute a Python script (from within php), which does take a good amount of time and am waiting for it to terminate so that I can process the output and print that out in HTML. The problem I'm having is that I can't get the PHP script to wait for the Python file to terminate. If I try it with a simple Python script say "print Hello, World!" it gets that. But anything that takes substantially long time, it just returns. I've tried system("myfile.py", $result) and $result results in a 1 and prints any subsequent prints in the PHP file. I also tried exec, with no luck. I've read through http://www.php.net/function.exec and the documentation presented in the "See Also" section with other commands. I haven't got anywhere yet, after much work. Any pointers, suggestions and fixes? -anuj