I seting up Light on my small ubuntu box. I've only transformed the sites-available-default/default

 <VirtualHost *:80>
    ServerAdmin webmaster@localhost

    DocumentRoot /home/user/Dropbox/www/
    <Directory />
        Options FollowSymLinks
        AllowOverride None
    </Directory>
    <Directory /home/user/Dropbox/www/>
        Options Indexes FollowSymLinks MultiViews
        AllowOverride None
        Order allow,deny
        allow from all
    </Directory>

    ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/
    <Directory "/usr/lib/cgi-bin">
        AllowOverride None
        Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch
        Order allow,deny
        Allow from all
    </Directory>

    ErrorLog ${APACHE_LOG_DIR}/error.log

    # Possible values include: debug, info, notice, warn, error, crit,
    # alert, emerg.
    LogLevel warn

    CustomLog ${APACHE_LOG_DIR}/access.log combined

    Alias /doc/ "/usr/share/doc/"
    <Directory "/usr/share/doc/">
        Options Indexes MultiViews FollowSymLinks
        AllowOverride None
        Order deny,allow
        Deny from all
        Allow from 127.0.0.0/255.0.0.0 ::1/128
    </Directory>

</VirtualHost>

After I connect with my localhost I recieve personal files in exchange. A PHTML using the index.php code.

After I connect with connect with http://192.168.1.133 I recieve a Forbidden error..

I suppose it's something related to permission and security, although not how you can repair it.

I'd exactly the same problem, also it was due to military services weapons php module for apache.

$ dpkg -l | grep apache
ii  apache2                               2.2.17-1ubuntu1                            Apache HTTP Server metapackage
ii  apache2-mpm-prefork                   2.2.17-1ubuntu1                            Apache HTTP Server - traditional non-threaded model
ii  apache2-suexec                        2.2.17-1ubuntu1                            Standard suexec program for Apache 2 mod_suexec
ii  apache2-threaded-dev                  2.2.17-1ubuntu1                            Apache development headers - threaded MPM
ii  apache2-utils                         2.2.17-1ubuntu1                            utility programs for webservers
ii  apache2.2-bin                         2.2.17-1ubuntu1                            Apache HTTP Server common binary files
ii  apache2.2-common                      2.2.17-1ubuntu1                            Apache HTTP Server common files
ii  libapache2-mod-auth-mysql             4.3.9-13ubuntu1                            Apache 2 module for MySQL authentication
ii  libapache2-mod-php5                   5.3.5-1ubuntu7.2                           server-side, HTML-embedded scripting language (Apache 2 module)

I believe (unsure) that libapache2-mod-php5 may be the essential package to operate php files with apache. So, make certain a minimum of you've that one installed, and check just a little about which packages to set up to possess a full php/apache installation. If you're setting up xampp, download the newest version and make certain you put in it as being root.