Trouble getting WordPress version 2.6 working

We have installed the WordPress version 2.6 on our IIS server. We have a php version 4.4.4 and mySQL version 3.23.49. We have not been able to install it. We get the following error “The specified CGI application misbehaved by not returning a complete set of HTTP headers errors”. In looking at some online help, we saw that we could replace the wp-includes/wp-db.php with a file posted on the forum. However this wp-db.php is not compatible with the newer 2.6 WordPress version. Is there any way we can fix this problem. Please help.

Thank you.