Chris, You said, "Perhaps you can take a step back and describe the whole process?" OK.
Page 1 collects firstname, lastname, email and sends the data via POST to page2.
Page 2 ASP checks the data for prior entry in the database, creates an appropriate nickname and the fullname, creates a database record if this is a new user and sends the data plus the values from several more hidden fields to an autoresponder via POST.
The autoresponder sends a validation email to the given email address and returns the user to page 3.
Page 3 is no more than a 'please click the link in the email when you get it' and a goodbye.
When the user clicks the link in the received email, they are returned to another page where their database record is displayed and they are invited to complete many other fields for their total profile.
We now have some clever person who wants to iritate us many times a week by completing page 1 with rubbish and just bombing out when page 2 displays. So we get a rubbish record every time.
Whew! That's the overview and the reason for looking for a simple way round it. I have another strategy in mind but it will need a significant amount of code re-write. Obviously, I'm lazy!