It looks like you most likely installed plug-ins that do not come with your bundle. Very often customers will install the Digi 002 Factory bundle plug-ins, which have plug-ins that are not in the Mbox2 factory bundle.
This page has info on which plug-ins come with your bundle - if it's not one of the plug-ins specified, then you would have to remove it or purchase it.
http://www.digidesign.com/index.cfm?...02&itemid=4945