When the property auth.forward.by.last.path is set to false, this causes a redirect loop(depending on what browser is used) and you will not be able to access the portal. Clearing the cookies will allow you to access the login page, but after logging in, you will be returned to the same error.
Steps to reproduce
1. In a new bundle of 6.1 GA1, add the following to your portal-ext:
2. Startup Tomcat/Liferay
Everything should start normally.
3. Logout of Liferay/stop tomcat
4. Set property to false
5. Start Tomcat/login to Liferay
6. Error messages pop up upon login