[roman]

A ver. Observa que tienes:

<Directory />
    Options FollowSymLinks
    AllowOverride None
    Order deny,allow
    Deny from all
    Satisfy all
</Directory>

lo cual deniega el acceso a cualquier directorio. Esto se sobrescribe en:

<Directory "C:/Archivos de programa/Apache Software Foundation/Apache2.2/htdocs">
    #
    # Possible values for the Options directive are "None", "All",
    # or any combination of:
    #   Indexes Includes FollowSymLinks SymLinksifOwnerMatch ExecCGI MultiViews
    #
    # Note that "MultiViews" must be named *explicitly* --- "Options All"
    # doesn't give it to you.
    #
    # The Options directive is both complicated and important.  Please see
    # http://httpd.apache.org/docs/2.2/mod/core.html#options
    # for more information.
    #
    Options Indexes FollowSymLinks

    #
    # AllowOverride controls what directives may be placed in .htaccess files.
    # It can be "All", "None", or any combination of the keywords:
    #   Options FileInfo AuthConfig Limit
    #
    AllowOverride None

    #
    # Controls who can get stuff from this server.
    #
    Order allow,deny
    Allow from all

</Directory>

pero el alias apunta a un directorio distinto. Luego entonces, deberías agregar:

<Directory "C:/david">
    Order allow,deny
    Allow from all  
</Directory>

// Saludos