This is an extract from our DNN Pivot Module manual.
Special Requirements IIS 6 (Windows 2000, 2003 Server)
If you are running II6 and wish to access the Microsoft Pivot Labs technology, you will need to enable some special configurations. To do this:
1. Login to your web server and start IIS
2. Browse to your Web Site or Virtual Directory for the website in question and Rick Click selecting Properties.
3. Select the Home Directory Tab / Configuration
4. On the Mappings Tab, select Add
5. The following data depends on what type of server you are running. 64 bit vs 32 bit, and if you have .net 4 installed or not. The only thing that changes is the path for the .dll file.
Add the following data: 64 Bit server with .Net 4 installed
– Executable: C:\WINDOWS\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll
Extension: .cxml
Limit to: GET
Script engine: checked
Verify that file exists: unchecked 
this gives you something like this above. Click OK and repeat the process for the following extensions:
– Executable: C:\WINDOWS\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll
Extension: .dzc
Limit to: GET
Script engine: checked
Verify that file exists: unchecked
– Executable: C:\WINDOWS\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll
Extension: .dzi
Limit to: GET
Script engine: checked
Verify that file exists: unchecked
– Executable: C:\WINDOWS\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll
Extension: .jpg
Limit to: GET
Script engine: checked
Verify that file exists: unchecked
Add the following data: 34 Bit server without .Net 4 installed
Not that the location of the four extensions described above will change, depending on your server status. As an example of the change for a 32 bit server without .Net 4 installed the location would change
From
C:\WINDOWS\Microsoft.NET\Framework64\v4.0.30319\
To
c:\windows\microsoft.net\framework\v2.0.50727\
So the location of the first file in the example above would be:
c:\windows\microsoft.net\framework\v2.0.50727\aspnet_isapi.dll
still giving a setup that looks the same but with a different path 
You can browse to your servers .net path (C:\WINDOWS\Microsoft.NET\Framework) to work out the location of the aspnet_isapi.dll file.
