You've got some stray frames floating out there beyond the end of your movie and their making the program think your project is longer than it is.
Press the \ key on your keyboard (above the Enter/Return key). This will show you your entire project on the timeline -- which in your case is probably a lot beyond the end of your movie.
Click and drag your mouse around that area beyond the end of your movie and the press the Delete key. This should snag and delete those stray frames. Press the \ key again and your project should display at its proper length and you can output a new disc at at the right length.
I ended up having to go to the EXPERT tab at the top, then scroll vertically through the tracks to find the one with anything on it past the end of my actual content and sure enough there it was. I'm good now! Thanks for responding.
Glad you found the issue, Justin! Please mark this question as answered. Thanks!