Fortunately, the Flashblock extension allows the users to provide a white list of the web sites that it will not block. You can input google.com to the list. That would work for the U.S. users. If you are outside of U.S., chances are that Google may localize its web site for you. For example, if you are in Canada, you should input google.ca. You can add both to the white list just to be safe:
Thanks to Ch for reporting this problem.
Update: You would have to add googleapis.com to the white list as well (please read Ch's comments).