As it turns out, the error message you have received is really a "feature" of CuteSITE Builder.
Obviously you want people to be fill out a form and send it to you. But what if someone is trying to be malicious and keeps pressing 'Send' and generates a ton of email repsonses to you? That's called "spamming".
So, Globalscape limits the number of emails that can be sent from any one computer to you within a specific time frame. Currently the limit is 7 emails per hour per IP address (computer).