When I run my HTML form from a pc with Internet Explorer 4.0 installed, I get a 500 Error/Server Misconfigured. The access log contains a 401 Unauthorized error and then I get a Premature end of Script headers message in the error log. The forms work when run on Netscape or the previous version of Internet Explorer. The IE browser runs from a PC on a local area network. The server, Apache 1.24b, is installed on a Dec Unix system. The HTML forms, c and perl scripts execute on the Unix system. The HTTP protocol for the IE is HTTP/1.1 and the HTTP protocol used by our version of Netscape is HTTP/1.0. I believe that a protocol difference in HTTP/1.0 and 1.1 or a problem with the way the Internet Explorer authentication method is set up could be causing the problem because I have been able to run some forms even after receiving these messages. Also forms using the POST request method are affected, but those with GET are still working.