The problem was solved by 1. Copying aspnet_client and ArcGIS directories to "<a href="file:D:/inetpub/wwwroot" target="_blank">D:\inetpub\wwwroot</a>". 2. Changing those paths to "<a href="file:D:/inetpub/wwwroot" target="_blank">D:\inetpub\wwwroot</a>". 3. Running the post installation.