Apache on port 81 with PHP 4

[jtsquared]

I'm running IIS and Apache on the same Win2K machine and I've configured Apache to serve pages on port 81. However, I need to run PHP version 4 instead of version 5 (for some other software). When I run the PHP switch batch file in xampp, it says it switches fine, but then I look at my php info and it's still on version 5.0.3. Also, if I try to restart apache after the switch, it gives me the error that it cannot initialize the module (and lists apache and PHP API's). It appears to start (after clicking OK on about 2 dozen of the same error messages) but still lists PHP 5 as the running version. Does anyone know if I can run Apache on port 81 and PHP4 at the same time and how I might get this to worK?

Thanks!