Hello Mrmrholmes,
If you have installed Cubase 6.5 (the full version) you shouldn’t need the Mp3 patch because the ability to export in MPEG1 Layer 3 if already available to you under File>Export>Audio Mixdown Window>Format>select MPEG 1 Layer 3.
If you don’t see this option under File, then please go to www.steinberg.net and under Support/Downloads make sure you have downloaded the latest version of the Cubase 6.5.5