PHP Authentication ( Header )

Hello, I've read all the postings in this ng and haven't anybody with the same problem as myself. So I hope someone can help me out. I'm trying to use the Header() function to authenticate users on my site. I doesn't work at all. I get a server error. ( will post errors bellow ) Now I can use Header() to redirect or even expire a page so it doesn't stay in the browers cache. But the following code gives me the errors bellow it. <?php if(!isset($PHP_AUTH_USER)) { Header("WWW-Authenticate: Basic realm=\"My Realm\""); Header("HTTP/1.0 401 Unauthorized"); echo "Text to send if user hits Cancel button\n"; exit; } else { echo "Hello $PHP_AUTH_USER.<P>"; echo "You entered $PHP_AUTH_PW as your password.<P>"; } This gives me the following error in my web browser. Server Error This server has encountered an internal error which prevents it from fulfilling your request. The most likely cause is a misconfiguration. Please ask the administrator to look for messages in the server's error log. I know this doesn't mean much to you so here is the error in the server log file. [28/Jun/2000:11:48:09] failure (25755): for host xxx.xxx.xxx.xxx trying to GET /test/test.php3, cgieng_scan_headers reports: the CGI program /usr/local/bin/php did not produce a valid header (name without value: got line "http/1.0 401 unauthorized") Everything else i have tried so far has worked. So i'm thinking it's something we forgot in the configuration of the server. Can anyone tell me where to start looking for a solution. Here is the server setup. Solaris 8 OS Netscape Enterprise Server PHP 4.0 compile as NSAPI Module Thanks JD