DEBUG DEBUG DEBUG
Since the page comes up correctly, before the form submittal, there are no syntax errors.
So the problem is a runtime error.
So start adding in debug.
The easiest way to do this:
If Action = "SendEmail" Then
ON ERROR RESUME NEXT
And then, after every operation that *MIGHT* cause an error, add a debug line. Just one example:
' If no input errors send the email
If Err.Number > 0 Then Response.Write "after error check, " & Err.Description : Response.End
You can just put in a few such lines to start with. If that doesn't find it, then add more, until you narrow it down.
I would personally expect the error to be in the actual sending code, but that email validation check looks ugly enough that who knows, the problem might be right there.