Nero Vision Express Error

I am using NVE to edit a wedding DVD. I am adding additional video files to it and setting up a menu. When finished, it says it is 5.6 GB. Too big. I reduce the quality setting and NVE burns perfectly. But, it is too grainy. So, I go back to NVE and try to Export it so that I can shrink it with DVD Shrink. Every time I hit the Export button, it immediately gives me an error message and shuts down when I hit okay. Any ideas to fix this?

Thanks in advance,