Item creator fails with fiu_vrowiki

If I try to add items using "fiu_vrowiki" as the site, it fails every time with every page with the message "Problem creating item". I'm not sure why exactly, but I imagine it could be because of the underscore or because the language code for the label should be "vro", not "fiu_vro" or "fiu-vro".

I haven't had any problems using it for other sites with normal two or three letter codes.