the Theme it stand alone extension is discontinued and should not be installed, a version of theme it is included in the Form Builder wizard.
make sure that you do not install eCart last, the install order i like to use is eCart -> Design Extender -> Data Bridge.
the current version of eCart is 5.0.7.
I would recommend uninstalling all of the WA Extensions you have installed, then reinstalling the current version of eCart followed by design extender an data bridge.
also, reset the workspace layout in DW to correct the floaters error:
go to Window -> Work Space layout -> Reset '<your layout name>'