So in other words. These lines right here
[8:07:21 PM:267] Building spell book
[8:07:21 PM:270] Spell book built
[8:07:21 PM:270] Compiling C:\Users\kyle\Desktop\HB\CustomClasses\fpsware.cs
[8:07:21 PM:474] Could not compile CC from C:\Users\kyle\Desktop\HB\CustomClasses\fpsware.cs!
[8:07:21 PM:475] File: fpsware.cs Line: 43 Error: The type or namespace name 'UIForm2' could not be found (are you missing a using directive or an assembly reference?)
See the bold part where you OBVIOUSLY just extracted the contents into the custom classes. It clearly says in his CC to do this
Installation instructions: this CC must be in a folder called Fpsware Death Knight.
If you still don't understand. Go into your HB folder and open the Custom Classes folder and create a new folder and call it Fpsware Death Knight IT IS CASE SENSITIVE!!! Then extract the downloaded contents into that folder