The Responder Windows Service uses browser-based configuration and management. It does this by hosting a mini-webserver and by using ASP.NET. By default, the Responder Windows Service runs under the limited-privilege "Network Service" user. When running on Windows Server 2003 you may see the following error when accessing the configuration page.

The current identity (NT AUTHORITY\NETWORK SERVICE) does not have write access to 
‘C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files’.

This appears to occur when IIS is not installed on the computer. You can easily fix this using a command prompt:

c:\>cd c:\windows\microsoft.net\framework\v2.0.50727
c:\>aspnet_regiis -ga “NT Authority\Network Service”

 This command will grant the appropriate access to the IIS metabase and other directories used by ASP.NET.