Board Thread:Lua Help/@comment-5068292-20150115153725/@comment-4522253-20150115232430

So, how to read that is that there's a problem on line 7 of Module:Navbox. In the case of yours, that means it's missing a require of Module:HtmlBuilder. It will also need Module:Navbar and Module:Arguments. Links to my copies provided, but you can get them from MediaWiki or Wikipedia and they are likely to work.