Jeff,
The one limitation to the Import of VOB files into CS 6 (that was added about the second update to CS 4, IIRC), is that the VOB's need to be 100% DVD-compliant. Most DVR machines, and a lot of software, with limited authoring capabilities do not create 100% DVD-compliant VOB's (usually the first VOB with navigation and Menus), and then the answer is to rip the MPEG-2 files from the problem VOB's.
If the VOB's were created with a program, like Adobe Encore, they WILL be 100% DVD-Compliant, and should Import just fine.
Hunt