ASPNET account permissions for web service?

[Jeff Mason]

I'm trying to set up a web service. This service needs to, among other
things, copy a file from a directory on my local machine to a directory on a
server elsewhere in my network.

Ultimately, the web service will be running on a server and will need to
access the files on both the client's machine and a file server.

For now, in development/debug mode I want the web service to run on my local
machine. When I try to do this, I keep getting errors when the service
attempts the File.Copy from the source to the target.

These errors are:

System.IO.IOException: The referenced account is currently locked out and
may not be logged on to

or

System.IO.IOException: Logon failure: unknown user name or bad password.

I'm pretty sure that these are a result of improper permissions on the
various shares, but what must I do on the system running the service, as well
as the file server permission-wise for its ASPNET account?

Thanks.