Thanks for your response. Let me see if I can clarify what it is I am asking.
The VW that I was referring to is the standalone product included in the Roxio Creator/EMC packages. When I talk about "playing " the files, I mean viewing the project in the preview window using the CD control buttons on the bottom of the preview pane. I am not using the VW that is part of the MyDVD project. I agree, putting the dmsm project files into MyDVD should be the last thing done before rendering and burning.
As for the projects I am trying to move to the 2010 product, several contain over 100 images, a few videos, sound tracks, sound effects, transitions from simple to 3D, pan and zoom effects, text boxes with animations, etc. It took a lot of work to put them together and I don't want to rebuild them from scratch. If I have to tweak a few things, that's OK.
The projects seem to migrate fine from C2009 to C2010 in the XP and Vista environments. In Win7 most of the stuff works as well, except for the background fill. Again, background fill migrates fine in the XP and Vista environments. One caveat though, I have not tried to render any of these projects using MyDVD yet. However, I can play dmsp files created in C2009 in the C2010 environment, so I am hopeful that step will work OK.
Perhaps you answered my question and I have been lucky to get working what I did get working. Do you know that Roxio's official position is to not support upward compatibility between releases? It sure leaves the customer between a rock and a hard place, wanting to move to an officially supported product on Windows 7, and not wanting or being able to, recreate weeks of work to get there.