‘Internet Explorer cannot display the webpage’ 2K8 R2 SP1 https

With Failed Request Tracing, you need to setup the rule, but as a separate step you must turn it on. In the Failed Request Tracing, check the Action pane on the right, that will have an option to enable it. That's my guess as to why the tracing isn't working.

My recommendation on any configuration in IIS7 where you have 1 site per app pool, or when all sites trust each other and the sites are stable, is to set Anonymous authentication to use the identity of the app pool. That gives you one less user to deal with. Then make sure that the app pool identity is granted permission on disk.

You mention that it doesn't work in the subfolder. It is possible to have different permissions or a different app pool used for a sub-application. Double check the app pool being used, and anonymous auth settings.

Finally, use Process Monitor as Colin suggested. Get it from www.sysinternals.com. It's free, safe to run on a production server and you'll figure it out in under 10 minutes. That will tell you exactly which user is denied access to which folder (or registry key).

The problem is with IIS web.config file for your site.

This article helped me overcome the issue: http://www.evanclosson.com/devlog/iis7httperrorsconfigurationonlockdown.

Have a read for this post on drupal groups: http://groups.drupal.org/node/25421

Otherwise you can use my config file below.

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
  <system.webServer>
  <!-- Don't show directory listings for URLs which map to a directory. -->
    <directoryBrowse enabled="false" />
    <rewrite>
      <rules>
        <rule name="Protect files and directories from prying eyes" stopProcessing="true">
          <match url=".(engine|inc|info|install|module|profile|test|po|sh|.sql|postinst.1|theme|tpl(.php)?|xtmpl|svn-base)$|^(code-style.pl|Entries.|Repository|Root|Tag|Template|all-wcprops|entries|format)$" />
          <action type="CustomResponse" statusCode="403" subStatusCode="0" statusReason="Forbidden" statusDescription="Access is forbidden." />
        </rule>
        <rule name="Force simple error message for requests for non-existent favicon.ico" stopProcessing="true">
          <match url="favicon.ico" />
          <action type="CustomResponse" statusCode="404" subStatusCode="1" statusReason="File Not Found" statusDescription="The requested file favicon.ico was not found" />
        </rule>
        <!-- Rewrite URLs of the form 'x' to the form 'index.php?q=x'. -->
        <rule name="Short URLS" stopProcessing="true">
          <match url="^(.*)$" ignoreCase="false" />
          <conditions logicalGrouping="MatchAll">
              <add input="{REQUEST_FILENAME}" matchType="IsFile" ignoreCase="false" negate="true" />
              <add input="{REQUEST_FILENAME}" matchType="IsDirectory" ignoreCase="false" negate="true" />
              <add input="{URL}" pattern="^/favicon.ico$" ignoreCase="false" negate="true" />
          </conditions>
          <action type="Rewrite" url="index.php?q={R:1}" appendQueryString="true" />
        </rule>
      </rules>
    </rewrite>
    <httpErrors>
      <remove statusCode="404" subStatusCode="-1" />
      <error statusCode="404" prefixLanguageFilePath="" path="/index.php" responseMode="ExecuteURL" />
      <remove statusCode="403" subStatusCode="-1" />
      <error statusCode="403" prefixLanguageFilePath="" path="/index.php" responseMode="ExecuteURL" />
    </httpErrors>
    <defaultDocument>
      <!-- Set the default document -->
      <files>
        <remove value="index.php" />
        <add value="index.php" />
      </files>
    </defaultDocument>
  </system.webServer>
</configuration>