CGI Error when uploading more than 15M

I get the error below when I try to upload image files to my photo gallery I'm building. Works fine when uploading files that together got size less than 15M. I'm running the photo gallery on a Windows 2003 server, using IIS and PHP 5.

Could it be that something times out or could it be that IIS is too fast for PHP cgi?

CGI Error

The specified CGI application misbehaved by not returning a complete set of HTTP headers.

I found a possible fix on the net. It was to add this code line before a redirect. But I can't find any way to do that in the script for the Image Uploader.

header("Connection: close");

Thanks, Scarabee!