The issue is most likely to do with your web server. For security reasons, many hosting companies now restrict who can receive forms using the sendmail function. Normally, if the receiving email address is associated with the domain, the form data will be transmitted just fine. If your hosting company offers PEAR tools, it is possible to send to email addresses anywhere. Essentially, these tools would allow your form to be routed via a password protested SMTP account. Many PHP form scripts will allow you to set this option up. Unfortunately, I don’t think this is an option with the Blocs form script - maybe sometime in the future it will be added.