I can not explain why, or offer a solution, but I can offer the observation that every time I have used a version of AutoCAD/ADT with a version of Windows that came out after that version of AutoCAD/ADT, I have found that the display of the file dialogs reverts to a list display, sorted by name, and I have to reset it to my preferred mode each time I start AutoCAD/ADT.
--
David Koch
Autodesk Discussion Group Facilitator
Using ADT 2004 at work; access to 2005, 2006, 2007 & 2008 at home