I'm getting an error after the "register with Facebook"

I'm getting an error after the "register with Facebook" process. I click the "register" button, Okay the access on Facebook, and then I get a security warning before I can return to the site:

"Although this page is encrypted, the information you have entered is to be sent over an unencrypted connection and could easily be read by a third party.

Are you sure you want to continue sending this information?"

Is there a way to make this warning not happen? Thanks!