The Idle Time-out within IIS can effect Ripplestone by closing the worker process before the session has timed out. This will cause an error within Ripplestone when you click on a link. This is because the worker process has been stopped due to inactivity and will result in an error like the one below.
The session timeout is set in the web.config file and the two setting (session timeout and the Application Pool Idle Time-out) need to work together. The Idle Time-out should be equal to or larger than the Session timeout value.
For example, if the session timeout in the web.config file is set to 30 minutes, then the Idle Time-out should be set to a value of 30 minutes or greater. In the screen shot below it is set to 35 minutes.