I had quite a lot of problems with PD9 build 2504. It did crash many times. And the Aspect ratio of the produced DVD was wrong. Even I selected 16:9 widescreen, the produced video was 4:3. On a Windows 7 64bit System.
For me it helped to uninstall PD9 completely. After that I installed the older build of PD9. I hope, there will be a better update soon.