Magento isn't displaying anything but a white homepage, in the error_log the error given is:
client denied by server configuration: /var/www/httpdocs/app/etc/local.xml
I can access the admin area fine, does anyone know why this might happen?
The log entry appears to be created by calls magento is making to ensure you have secured your admin properly. Rather than it being an error it is actually something you want to see as it is effectively saying your admin is secure. Clearly this is just noise in your logs.
There is a really elegant solution on how to fix this and speed up your admin page load described here: http://www.yireo.com/tutorials/magento/magento-administration/1322-client-denied-by-server-configuration-appetclocalxml
Essentially create the file in the location below with the contents shown. Once you have added the file:
app/design/adminhtml/default/default/layout/local.xml
With the contents:
<layout>
<default>
<remove name="notification_security" />
<remove name="notification_survey" />
</default>
</layout>
Remember to flush your caches: System > Cache Management