for the floaters errors, reset the workspace layout:
go to Window -> Work Space layout -> Reset '<your layout name>'
for the other error, what versions of the extensions are you installing?
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.