So i ran across this issue while trying to change my installation's region from it's default USA option. I noticed there were no other choices, and the display languages were also limited to the built in ones. Clicking the (+) sign at the bottom of the window brings up a blank window with a search bar at the bottom, but i can't search or choose anything different.
I'm running LMDE 201204, x64.
Any help would be appreciated!