(401) Unauthorized - .NET 2.0 Web Service

I'm attempting to write a .NET 2.0 Web Service to upload a file using a specific user ID and Password.
I need to avoid using the ASPNET machine account for security issues.

Here is my exact code snipet:
My.Computer.Network.UploadFile("C:\sample.log", "http://localhost:3477/wsFileUpload/Uploads/sample.log",

"Uploaduser", "testuser11")

I'm receiving the following WebException error:
The remote server returned an error: (401) Unauthorized

I am attempting to run this on my LOCAL PC in the development environment.
VWD 2005 Express created a \WebSite1 and I added an "Uploads" folder.

With "Uploaduser" on my PC I set it with all-access to the "Uploads" folder.

As far as web.config:
<authentication mode="Windows"/>
Nothing else exotic.

I am assuming I missed something basic?

Thanks!

Have you added write access for the Uploads folder to the "Network Service" account (using 2003 Server) or "ASPNET" account in Win XP?

That did the trick!  Thanks!

-Dave