Delete the Dreamweaver Cache file from the users configuration folder:
If you continue to have a problem, please provide some more details on what steps you are taking up to when the error occurs.
What Application Preset are you using?
Are you using your own table? or checking the box to have the table created for you?
at what step of the wizard do you get the error?
On the first screen? The manage pages tab? In the Field settings screen?
Please provide as much detail as possible.