Hi - as it stands moodle on RACHEL can only work if the RACHEL was built with the 2.1+ installer (you can see this on your RACHEL "version" page in the admin section. If your installer is earlier than 2.1, you'll need to do a system update via USB. Let me know what version you have - instructions on updating the system via USB are forthcoming.
As to the two versions - use en-moodle; that is the one that is tested to work. The other was part of some future plans, but I have hidden it for now. Thanks for the info!