[Plugin: Contact Form 7] Help: Duplicate websites: localhost = fine, live site = problem..?

Hey guys,

As the subject line really. I have two exact versions of the site; one hosted locally and one hosted live with my web host.

Contact Form 7 works fine locally, delivering my messages, but on the live site – nothing.

Could anyone suggest – apart from the obvious – which aspects of this plug-in my host should take a look at, or amend, please?

Thanks in advance,