UPDATE: Apparently my CD-Rs work and I used to use DVD-Rs and they worked, but ever since I tried burning things on DVD+R, I'm getting error messages on boath Toast 9 and Disk Utility...
Have you tried creating a new user account and burning your disc from there? Sometimes your account can get corrupted over time and cause things to get a little screwy. This will help determine whether you have a hardware problem with your burner or just a software problem.
Well I went on Apple's forums and apparently this has happened to other users. Some with DVD+Rs others with DVD-Rs. I just went out and bought a few DVD-Rs and it works. I'm going to get the lens cleaned in the superdrive and go from there I suppose..