A number of WebmasterWorld members who use Google's Blogspot application are reporting that when they log into Google Webmaster Tools, they're getting a lot of errors that many URLs are being restricted by robots.txt. However, blogspot.com users have no control over the robots.txt file (and as far as anyone is aware, such a file cannot be created).
One example of this problem is explained:
I've noticed that if there's a 301 redirect from Page A to Page B and Page A is disallowed in robots.txt then Page B will be reported as Restricted in robots.txt in GWT.
Nobody knows of a fix at this point, and the negative impact, if any, is undetermined.
Forum discussion continues at WebmasterWorld.