Thanks for the detailed report. Don't worry about your step #4, you didn't get to that point.
From what I can tell, you're opening up BrowserLab in your browser first, then trying to do a preview from Dreamweaver, is that correct? I'd like to try a test where you first test BrowserLab in standalone mode and if that works, then try the BrowserLab integration with Dreamweaver. So please try doing the following steps:
- Close Dreamweaver and all of your browser windows.
- Leave DW closed, open a single browser window and go to https://browserlab.adobe.com
- Log in, and request a screenshot by typing in a URL like http://www.yahoo.com and pressing <Enter>
- Does that work for you? Do you get screenshots for that? If not, please describe the steps you followed and what you see
- If so, close your browser window and open Dreamweaver. Do not open your browser to BrowserLab
- In DW, open the webpage you'd like to view in BrowserLab and press the preview button in the BrowserLab panel as shown in your shot
- You may need to log in again, but let me know what happens with that test.