Everyone having this problem with "order number does not exist" when you try to look up the order on our site - there are two things you can do:
1) Wait for the email we sent with the direct download link for ep2. You should have it within the hour.
2) Go to www.findmyorder.com
and fill in your order number and password there. It's Digital River's version of the same form on our site.
-Emily, Telltale Games