Rated 5 out of 5 stars

This add-on is one of my all-time favorites, but when I try to install it now, i get an error message saying that Firefox could not install the add-on because of invalid file hash. I noticed that the add-on was recently updated, so maybe this is the issue.

This review is for a previous version of the add-on (0.9.7). 

I think that addons.mozilla.org had a failure this morning. It should work now, but in case it doesn't, you can also use the "alternate" install from the homepage:
http://downloadstatusbar.mozdev.org