When you install the latest stuff if if it asks if you want to overwrite stuff always choose yes. If you don't overwrite the older sysvars when it asks you to DB will still work but it won't let you use any of the newer syvars.
If it doesn't ask you to overwrite stuff you don't need to do it manually though, not any more, our esteemed programers have got the whole thing pretty much sorted on that front.
Hope that helps. If you are still having problems we will be happy to try and sort them out!
Sorry about the *.pain thing confusing you btw, was just an inhouse joke, sort of like it's cruel to make your bot feel pain. Maybe something that should be removed from the Wiki in future to stop other people getting confused.