The Data Assist Version in Data Bridge is version 3, DataBridge is essentially Data Assist 3 plus a consolidation of the Data driven extensions.
the install order with Data Bridge should be:
Design Extender 1.0.4
Data Bridge 1.0.0
before uninstalling the extensions it is quicker if you rename the configuration folder, for help finding the configuration folder location, see the common installation issues PDF:
cose the extension manager and Dreamweaver, then rename the configuration folder. When you open the extension manager, the extensions will be unchecked to be disabled. select each one then click the delete button,m the delete should only tack a moment since they are disabled.
then you can install eCart, Design Extender and Data Bridge. make sure to use the latest version, and install in the correct order.