Secondly, MMM is an app in HBC on your sd card. It has nothing to do with updating your system menu version.
Third, there is no need to uninstall anything to resoftmod. You are just asking for a brick if you start uninstalling stuff without knowing what your doing.
So what you want to do is follow the softmod any wii guide. (link is in the spoiler below) This will update all your IOS, cIOS, apps, and give you much needed update blocking and brick protection.
While your at it, stop by the Introduction section and say hi. You will be greeted with a lot useful info on how the softmod works.