A couple weeks ago, we reported Google opened up invite requests to join a beta of the structure data dashboard.
I signed up immediately and yesterday, I, along with other webmasters, received my welcome email to take a look at the report.
To sign up, you can do so at over here – I am not sure if they are still welcoming beta testers. That being said, if you did sign up, you can see if you have access to the new Webmaster Tools structured data error reports by going to the “Optimization” section and checking within the “Structured Data” section.
Here is his screen shot, click to enlarge: