If you recently upgraded Unity to 5.1 and started experiencing issues with RAIN, double check your version in RAIN -> Help -> About and make sure you are running RAIN 2.1.11 or greater. There was a significant API change in Unity that pretty much breaks RAIN 2.1.10 and below in Unity 5.1.
You can get the latest RAIN on our download page or at the Unity Asset Store.
Also I just discovered a mistake with our updating, so the menu updater should be working again as well if that is the way you prefer to update.
Thanks, and sorry for the trouble.