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

I have developed my first php pages using dreamweaver and I am receiving a "CGI application misbehaved by not returning a complete set of HTTP headers".  My site is hosted (they maintain softare, W2, PHP, mysql, etc)  The sample web page that generates the error is www.aosweb.org/test.php. It is a very simple php script.  I have already submitted a help ticket to my hosting provider for this issue.

As I need to get php pages deployed, I am also trying to this issue by eliminating the following possibilities:

1.  Router on my home computer.  Do I need to open any ports.

2.  I run Norton Internet Security with a firewall.  I noticed there is a firewall setting in manage sites, but I do not currently use this.

3.  Do I need to open any ports for Norton.

Since my ISP runs all the software, I do not think the above issues would cause the issues but I thought I would try to cover all basis.

Thanks.

George