The alternative script was for older versions of DNN.  But that post also has the information needed to update the DB.

I really don't understand why the OpenSesame.aspx page could not be reached if you uploaded it to your root dnn folder.
Maybe it was just a mis-spelling on the Url?

This has been brought up many times.  The only reason I created the work-around(s) was because the core team decided that they would not change the current behavior. 
The reason being that if you set your login to an alternate page then there should not be a way to circumvent it or it could be used as a back door.

It never hurts to voice your opinion though, and to be sure you are heard you may want to add it to http://support.dotnetnuke.com