LiveSite PageType Config Error

If you get the following error message when viewing a page in the LiveSite Runtime environment:
“Error 500: Filter [runtime.filter.OpenSessionsInView]: could not be initialized”
Please check the pagetype-config.xml file as this may have an error in it. This is usually located in the following folder:
…/WEB-INF/conf/livesite_customer
In case you have lost your working version of this file you can find one here.