Some ideas:
1) Check the System Even log under Applications and see if there are any errors.
2) Try the following URL in a browser: http://localhost/mapguide2010/mapagent/index.html. Execute the EnumerateResources by hitting the submit button the default page.
3) Can you log into the Site Admin: http://localhost/mapguide2010/mapadmin/login.php
4) Which instance of the API did you install? PHP or .NET. If you previously had 2009 installed check your system path for an entry pointing to PHP in a 2009 folder and remove the entry.
5) Try reinstalling the WebExtensions using Apache instead and add the :8008 port to the URL.
Dave