Correction, all my browsers work: Safari, Firefox, Opera, OmniWeb, Chrome, and iCab. I didn't have hava enabled in the browsers that failed. Once enabled they worked too.
So maybe you are having a security certificate handling problem. Check the browser preferences.
I am not really sure what you have to do to get around this. Two general ideas are,
1. Safari preferences, Security, check checkbox at bottom about "Ask before sending a non-secure from from a secure website".
2. Open the Keychain Access (in Utilities) and look around to see if somehow there's already a certificate for the site that is somehow causing the problem and delete it. Not sure what name you need to look for ("Oracle"?)