I've got everything configured and created for this Tutorial.

However, when I run it, including the included test app -- (and based on the docs it appears I should be able to run this from my local computer) -- 
the Outbound Messaging Sample Tester prompts me for my SalesForce credentials.  I type them in -- using my Developer License login (and security token), which is where I created the Outbound Message wsd, but it won't accept my credentials.

Do I need to turn something on in my developer org to accept these calls?