It looks like you opened the Proto file directly, which will not work since it is a binary file.
Do you have the Proto for Dreamweaver extension installed?
http://labs.adobe.com/technologies/protoextension/
If you're using CS4 or earlier, you'll need to extract the contents of the Proto file using an archive utility (e.g. WinZip, WinRAR, Mac OS Archive Utility, etc.) and then you'll be able to open the .css and .html files in Dreamweaver.
North America
Europe, Middle East and Africa
Asia Pacific