RmCommons should never be hidden because it is the base for other modules. You also need to have a specific theme in place to be able to access stuff as well.
To properly do this you had to have changed your theme back to a non RmCommons theme after also disabling the modules dependent on it.
I am not sure if RmCommons was ever released as a stable version and was only a beta version. Hopefully RM will respond to you shortly.
what theme are you using in the admin, also what modules are you using for your site that depend on RMCommons?
Attending College working towards Bachelors in Software Engineering and Network Security.