I get the same thing in Firefox, and in IE it shows the lock correctly. The page is secure.
If you double click the lock icon, then click the security tab you can see it says "Connection Encrypted: High-grade Encryption...The page you are viewing was encrypted before being transmitted over the Internet. Encryption makes it very difficult for unauthorized people to view information traveling between computers. It is therefore very unlikely that anyone read this apge as it traveled across the network."
I noticed that sometimes when I load the page I get the lock with the cross through it, and sometimes not.
If you use IE it prompts you to ask if you'd like to not load any portion that is not HTTPS. Firefox doesn't have that feature. The only thing not loading HTTPS is our Google analytics link. Of which nothing concerning your credentials is sent unsecurely. I'll see if we can get a HTTPS version of that functionality from Google.