Hi Carmen,
You can download the latest version here: https://support.quest.com/toad-for-oracle/14.0
It is 14.0, not 15.0.
The beta will not run unless 14.0 is installed. So after you have 14.0, you can get the beta here: Toad for Oracle 14.1 Beta
I'm sorry, I don't remember the details of the support case. Do you have the SR# so I can look it up?
-John