Assuming you are using Dreamweaver CS6 and updated it to the latest version, be sure to check out this post for a possible solution to that part:
In the browser, BrowserLab seems to be working just fine here.
I recommend that you (a) update Flash Player to the latest version and, if that does not resolve the issue, (b) clear your Flash Player cache and your browser cache and cookies.
If you're using Chrome, Flash Player gets updated along with Chrome updates. Go to settings > About Google Chrome to check for an install any available updates, then restart Chrome to apply the update when it prompts you.
If you're using any other browser, go here for updates: http://get.adobe.com/flashplayer/
For instructions on clearing your Flash Player cache, see: http://forums.adobe.com/thread/977699
Clearing the browser cache & cookies varies by browser, but this document has a general guide that should get you close: http://forums.adobe.com/docs/DOC-1744
