Problem Submitting Form To Its' Same Page?

I'm trying to submit a form to the same page. Eg. (page name = test.asp)

<form action="test.asp" method="post" name="testform">
<input type="text" name="testval1">
<input type="submit" value="Go">
</form>

At the very top of the page I try to get the value by saying:

newtest = Request.Form("testval1")

I got the example from here

The trouble is, my page instantly throws an error. I think it's because when I first load the page up, it's obviously not coming from a form submit! Can anyone shed any light on a way around this?