Appache2 - client denied by server configuration when using dynamic ip for access

[simpoon]

I have installed moodle on Ubuntu 11. Everything is OK when worked as Intranet. Recently, I wanted to provide the service to the public using dynamic ip. However, the system always returns error Page 403 Forbidden. In the errorlog file the following error was found.

[Sat Aug 06 12:38:23 2011] [error] [client 192.168.1.98] client denied by server configuration: /media/LinExt3/www/moodle/

My config file in sites-available directory is as follows

<VirtualHost *:80>
ServerAdmin simxxxx@hotmail.com (simpoon8@hotmail.com)
ServerName vlearners.sytes.net
ServerAlias *.vlearners.sytes.net
DocumentRoot /media/LinExt3/www/moodle/
<Directory />
Options FollowSymLinks
AllowOverride None
allow from all
</Directory>
<Directory /media/LinExt3/www/moodle/>
Options Indexes FollowSymLinks MultiViews
AllowOverride None
Order allow,deny
allow from all
</Directory>

#ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/
ScriptAlias /cgi-bin/ /media/LinExt3/www/cgi-bin/
<Directory "/media/LinExt3/www/cgi-bin">
AllowOverride None
Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch
Order allow,deny
Allow from all
</Directory>

#ErrorLog ${APACHE_LOG_DIR}/error.log
ErrorLog /media/LinExt3/www/error.log

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

#CustomLog ${APACHE_LOG_DIR}/access.log combined
CustomLog /media/LinExt3/www/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>

The file permission for moodle directory is as follows\
drwxrwsr-x 34 www-data www-data 4096 2011-07-21 23:39 moodle

Appreciate someone can help me to resolve the problem

Thanks in advance

Simpoon :(