On some browsers (particularly Firefox or Mozilla) the prompt may say something to the affect of:
"Security Warning: Although this page is encrypted, the information you have entered is to be sent over an unencrypted connection..."
Some elements of the website are unencrypted (general text and images) however, all of your personal information, username, and password are transmitted safely over a secure, encrypted connection, and are stored in our database completely securely. The browser in this case is just trying to assist and make you aware that some of the information on the page is not secure (again - your information IS secure).
To remedy the issue, simply hit "continue" and everything will work as normal.
Here's an example of the prompt you may be receiving:http://www.panachedesai.com/images/outside/encrypted.jpg