Same problem here. Clicking on Rip Disk does nothing. When I drag the CD onto MC, it accesses the disk for a moment and then nothing.
You don't drag the disk into MC.
Open Drives and Devices in the tree in MC, select the dist there and it will popup a track listing. Then do Rip Disk.
In System Preferences you should set the action for inserting a CD to Ignore and in Security and Privacy MC needs access to removable drives.
I just did this yesterday on a test Mac and it was fine with both internal and a USB drive.