For the error, reset the workspace layout:
go to Window -> Work Space layout -> Reset '<your layout name>'
and Delete the Dreamweaver Cache file from the users configuration folder:
http://www.webassist.com/tutorials/Common-installation-issues
when you use the Add content to power cams interface, it should launch the installer automatically. normally when it fails to launch, it is because the testing server is not configured properly, or if using a local testing server has not been started.