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Thank you for your interest in PHP.

I install apache first then unzip php to c:\php. And I unzip mysql to c:\mysql and start the mysqladmin.exe up. And than I change the setting of apache's config file(httpd.conf), I add three more lines:
ScriptAlias /php/ "c:/php/"
AddType application/x-httpd-php .php
Action application/x-httpd-php "/php/php-cgi.exe"

Then I edit php.ini file:
extension=php_mysqli.dll
extension_dir = "C:/php/ext"

Then I restart apache. And I unzip phpmyadmin to the apache htdocs folder.
I changed the phpmyadmin config file(config.inc.php):
$cfg['Servers'][$i]['extension'] = 'mysqli';
$cfg['Servers'][$i]['auth_type'] = 'http';

Then I open the browser to login the phpmyadmin.
Type the user name and password, and it keep saying the username or password is wrong. I'm sure the username and password is right.

If I change the apache config file(httpd.conf):
LoadModule php5_module "c:/php/php5apache2.dll"
Add Type application/x-httpd-php .php
PHPIniDie "c:/php"

Then restart apache, everything works fine. I can login phpmyadmin normally.

I think there are some bugs in the php-cgi.exe file. It can't get the right username and password information from me. I can only login with phmyadmin setting:
$cfg['Servers'][$i]['auth_type'] = 'config';

But not the http mode.
But if I load php as a apache module, I can login both config and http modes.

My software versions are:
Apache 2.0.53
php 5.0.4
mysql 5.0.3
phpmyadmin 2.6.2 beat1
All of them are the newest.

Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.php.net/manual/ and the instructions on how to report
a bug at http://bugs.php.net/how-to-report.php

"The HTTP Authentication hooks in PHP are only available when it is running as an Apache module and is hence not available in the CGI version." (c) http://www.php.net/manual/en/features.http-auth.php