Select Preferences from the Tools drop down menu. Then click the check button for All located in the bottom left corner of the preferences menu.

Click on Main interfaces under the Interfaces tab, then check both the Web and Lua interpreter boxes.

Now click the arrow next to Main interfaces to expand that tab and select Lua from the items below it. Finally locate the Password box in the Lua HTTP section and type something into it.

Hit Save, restart vlc and enjoy.