Using Cygwin tar.exe on Windows

I have a little application I have built that will create a tar.gz archive of a group of files and directories. It works flawlessly on FreeBSD, OSX and Debian Linux. I want it to work for Windows, but I am having some trouble. I am simply using an exec call to the tar application: exec('/path/to/tar -czf /path/to/myarchive.tar.gz file1 file2 dir1'); I have Cygwin installed on my Windows box (WINNT), and it includes a tar binary located in: C:\cygwin\bin\. When I use this command: exec('C:\cygwin\bin\tar.exe -czf C:\path\to\myarchive.tar.gz C:\path\to\file1 C:\path\to\file2'); I get nothing - as in the exec returns NULL and no archive is created. I have confirmed this by providing the second parameter to exec() and dumping it - it's always NULL. I have two questions: 1. Why doesn't this work? 2. Is there a better/easier way to create a tar (or ZIP) archive on Windows (through PHP)? I will happily implement something else for those who must run inferior OS's. Thanks, -brian muldown