"unable to find file wa_themeit.html in the configuration/floaters directory"
That implies the extension was not installed properly. Please try to reinstall the extension, the file it claims it cannot find is definitely in the extension package and should be found if installed properly.
You could look to see if you can find the file... in windows explorer, type in the path: %appdata%
Then click on Adobe and the Dreamweaver version you are using. From there you should be able to find Configuration/Floaters and check if that file exists that the error claims cannot be found. If it is there, try closing Dreamweaver and deleting the winfilecache .dat file whith Dreamweaver closed.
If this doesn't work, then post back and we can create a support incident to investigate this with you directly.
