Errors stating proc_open() is not available on this server

This error indicates that your host has disabled the proc_open function in php.  This function is required to connect to an external SMTP server to send mail.  You will need to go to FormSnap Base and go to SMTP Settings.  Set the USE SMTP checkbox to DISABLED.  Then republish your project and test.  This will allow the form to pass the mail off to the web server to delivery directly via phpmail (assuming your host has not disabled that on you also!)