Compiler Error Message: CS0234: The type or namespace name 'ForumPages' does not exist in the namespace 'YAF.Classes.Utils' (are you missing an assembly reference?)

Line 38: private YAF.Classes.Utils.ForumPages _page;

Before I follow some of the suggestions I saw when I googled and start installing a bunch of DLL references, what is the RIGHT way to resolve this? And yes, I did modify the app config