Windows 8 Release Preview it should be stressed is not supported, this thread is simply a reference for anyone playing the game on it that is encountering an issue where the launcher is getting stopped on the "Examine" stage.
You can work around this issue by manually moving the files out of the 'Patches' folder and into the main "Dungeons and Dragons Online" folder with the launcher closed.
Open the 'Patches' folder found in:
C:\Program Files\Turbine\Dungeons and Dragons Online
C:\Program Files (x86)\Turbine\Dungeons and Dragons Online
Inside of the Patches folder, copy all the files and paste them after navigating back into the Dungeons and Dragons Online folder, choosing the "Copy & Replace" option when asked to overwrite the files that already exist.
Relaunching the game will allow it to proceed updating and launching.
NOTE: Windows 8 is not currently supported.