[Plugin: Contact Form 7] no confirmation or error messages

Contact Form-8 works perfectly on my site, except that no send conformation or error messages show up after clicking the send button. I receive the emails, so there’s no problem there.

I have tried adding the tag [response] at both the top and bottom of the form, but still no green box or red box or message or anything.

I have tried bad email addresses and such, but the page just refreshes, and that’s it.

I have tried it with FF, IE, Safari, Opera, Chrome…no difference.

I only have two widgets in my sidebar – a standard text/html widget that I use as a spacer, and the standard meta widget (admin, login, etc.), so I don’t think they are causing any problems.

Here’s a question that will point out how new I am at this: at the bottom of the settings page, there is a list of message tags. Am I supposed to do anything to activate any or all of them?

Any suggestions would be greatly appreciated.

Thanks,
~Dale