I'm just guessing, but it might be that your IE settings are so high that it doesn't allow you to use unsecured/unencrypted forms.
Have a look in your Security Tab in Internet Options, click "Custom Level..." and locate "Submit nonencrypted form data". If that is set to disabled, then that could be the problem. If not you might want to have a look at the other options in IE or your IE SPYAD. My guess is that IE-SPYAD has set your IE security setting very high.