ON LOCALHOST System.UnauthorizedAccessException:

Question

I have developed a login page in asp.net which impersonate the user  using ASP.Net  IMPERSONATION and then redirect it to the specified page where i m giving IP Adress to my webserver and then reading a file from "C" Drive of my webserver. The code and impersoation works fine as i run it in Visual Studio 2005 i m impersonation using Domain Administrator account who can acess any drive of the entire network but as soon i host it on my local pc and try to  run it using localhost it gives me System.UnauthorizedAccessException: Access to the path '\\WebServer\c$\Test.txt
I m trying to play with IIS 5.0 secuurity tab for this application but still not getting it to work plz help me Thanks in advance