Note.: Forgot to mention I'm on a 24" iMac with OSX 10.6.8. :3.
For those of you who are on a Mac, and the Speaker's Audio option doesn't appear in the Audio Mixer, I think I found out a semi-solution for this issue. What I first did was follow the reinstallation process of deleting the extensions and the application. However, that didn't work. So then I simply download the previous version, 20.3.0. That did solve the issue.
Now this is not a solution for version 20.3.25, and maybe I just got lucky. But I'm posting this just in case this does do the trick. This is only if you don't mind using a previous version. I hope this does work for those who are having this same issue. :3.
Download version 20.3.0.: http://www.livestream.com/userguide/...0_of_Procaster