First off you said you host at GoDaddy:
I have two other customers who have been having problems with email today, both on GoDaddy also. One changed the from email address in Form Master to the same one which is used when testing the SMTP settings in Host Settings, and all worked. I assume GoDaddy has made a change to their SMTP server security or they are having problems authenticating SMTP requests. You might want to open a ticket and ask if there has been changes, and if not ask them to help you debug the issue.
If you find out anything I would appreciate knowing.
Secondly:
If you login to Snowcovered as the same user who purchased the DNN3 Versions you will get the DNN4 Version for half price. You don't need to first get the PA as the Source Version comes with the PA.
Glad you like the module, and be sure the let me know if you still have problem.