chris_johnson0

I solved the riddle! After a lot of snooping around the internet, I found an old WordPress installation page for WPMU. Here is a link.

http://codex.wordpress.org/Installing_WPMU

I copied the code in the IIS section and pasted it into my web.config file. Presto! The backend link now works for the subdirectory site and it fixed another problem I had with the CSS not being displayed on the subdirectory site.

Here is the code in my web.config file.

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <system.webServer>
        <defaultDocument>
            <files>
                <add value="index.php" />
            </files>
        </defaultDocument>
		<rewrite>
			<rules>
				<rule name="Imported Rule 1" stopProcessing="true">
					<match url="^(.*/)?files/$" ignoreCase="false" />
					<action type="Rewrite" url="index.php" />
				</rule>
				<rule name="Imported Rule 2" stopProcessing="true">
					<match url="^(.*/)?files/(.*)" ignoreCase="false" />
					<conditions>
						<add input="{URL}" pattern=".*wp-content/plugins.*" ignoreCase="false" negate="true" />
					</conditions>
					<action type="Rewrite" url="wp-content/blogs.php?file={R:2}" appendQueryString="false" />
				</rule>
				<rule name="Imported Rule 3" stopProcessing="true">
					<match url="^(.+)$" ignoreCase="false" />
					<conditions>
						<!--# add a trailing slash to /wp-admin-->
						<add input="{URL}" pattern="^.*/wp-admin$" ignoreCase="false" />
					</conditions>
					<action type="Redirect" redirectType="Permanent" url="{R:1}/" />
				</rule>
				<rule name="Imported Rule 4" stopProcessing="true">
					<match url="." ignoreCase="false" />
					<conditions logicalGrouping="MatchAny">
						<add input="{REQUEST_FILENAME}" matchType="IsFile" ignoreCase="false" />
						<add input="{REQUEST_FILENAME}" matchType="IsDirectory" ignoreCase="false" />
					</conditions>
					<action type="None" />
				</rule>
				<rule name="Imported Rule 5" stopProcessing="true">
					<match url="^([_0-9a-zA-Z-]+/)?(wp-.*)" ignoreCase="false" />
					<action type="Rewrite" url="{R:2}" />
				</rule>
				<rule name="Imported Rule 6" stopProcessing="true">
					<match url="^([_0-9a-zA-Z-]+/)?(.*\.php)$" ignoreCase="false" />
					<action type="Rewrite" url="{R:2}" />
				</rule>
				<rule name="Imported Rule 7" stopProcessing="true">
					<match url="." ignoreCase="false" />
					<action type="Rewrite" url="index.php" />
				</rule>
			</rules>
		</rewrite>
    </system.webServer>
</configuration>

I hope this helps someone else using WordPress 3 and IIS 7. Thanks.