It would be on disc 1, not the bundled applications install disc which has stuff like iLife on it. Using the "Go To Folder" command in the Go menu of Finder, with the following path: Volumes/Mac OS X Install Disc 1/System/Installation/Packages/ should bring up a Finder window inside of which is a BootCamp.pkg file. Double-click it to reinstall that Boot Camp Assistant to /Applications/Utilities, then use the restored Boot Camp Assistant application to remove the Boot Camp partition.