Got one more thing that you might want to try, take the video that you're about to burn and run it through a compression program such as TMPEG before you blast it into your DVD writing software.

Here is the deal, I was doing the same thing that you were doing and found that I was only able to burn 1 hour of video to a DVD and not 2 hours. I took my DVD Player and started to watch movies in a diag mode and found that the Hollywood blockbusters were hitting my screen at variable bit rates rarely higher than 5mbps (my movies were set at 8mbps constant).

I ran one of my movies through TMPEG and set the bitrate at 4mbps and compressed the video to where I could fit 2 hours on a 2 hour dvd. There was one more catch, the audio compression in TMPEG stinks, my Hollywood movies show where audio averages 384kbps, the video output that I'm burning is at 1.5mbps which is HUGE! I found an article on the web about using TMPEG and re-compressing the audio, however my authoring program (Roxio) won't allow for a seperate audio and video file so this solution is out for me.

Hope this helps you a little....

Miguel