Impersonation Configuration Error

[Mills Perry]

I have entered an identity element in my Web.Config file:

<identity impersonate="true" userName="myDomain\myUserid"
password="myPassword" />

When I try to run my application, I get this error:

"Could not create Windows user token from the credentials specified in
the config file. Error from the operating system 'A required privilege
is not held by the client. '"

I have added my ASPNET account the Super User and Administrator groups
and restarted IIS, but that didn't help.

I have also tried updating my Machine.Config file without success.

<processModel enable="true"
... blah blah blah ...
userName="myDomain\myUserid" password="myPassword"
comImpersonationLevel="Impersonate"
... blah blah blah .../>

Can someone tell me clearly (using small words and specific steps)
what I need to do to use the <identity> tag?

Thanks!