Are you following the directions in the WUDump thread? WUDump gives you 12 parts of a wud file that you have to join on the pc, then extract the wupinstall style files (.app/.h3/title.*) from there using wud2app, and copy those to sd, THEN install. If you wanted to extract the files directly from disc so they're ready to install, you wanted Disc2App, not WUDump. Depending on the disc and your computer skills, it might be fastest to just redump the disc with disc2app.