Bitnami redmine on Windows - upgrade from 1.2 to 2.1 - rake no such file

I have an existing Bitnami Redmine install - running Redmine 1.2. I am trying to upgrade it to 2.1. I installed the software, restored DB from backup of the old. When I try to run

rake generate_secret_token

or any rake command I get

no such file to load -- C:/Program Files/BitNami Redmine Stack/apps/redmine/config/environment

The config/environments folder are in C:\Program Files\BitNami Redmine Stack\apps\redmine\htdocs\config\environments and environment.rb is in C:\Program Files\BitNami Redmine Stack\apps\redmine\htdocs\config\

How do I fix this issue?