A bug seemed to have been introduced where the session value is checked and if the site web configuration file does not have session enabled, it throws an exception. We will update the code and provide an updated download bits. In the meantime, try enabling the session to see if it helps (web.config <pages> tag with enableSessionState="true"). Note this is optional, it does not require you to enable the session when this bug is fixed.
I will update this thread once we have updated the download link.