Can you provide more details on how you are setting the emails up please?
Who is your host? the settings to use for sending emails are dependent on your host.
a copy of your form page and the webassist/email folder would be helpful.
also make sure you are using the most recent version of Data Bridge, version 1.1.3. If you have a previous version installed, make sure to uninstall it from the extension manager before installing the newer one.