Can't tell from your post as to what your status/environment actually is. Are you trying to do this through a PXE boot environment or are you using some type of third party imaging program like Acronis True Image, Ghost or Windows startup repair. Can you confirm that you actually do have a network connection by pinging the server that holds the backup files / image. Can you browse or UNC to the file/folder location, what is producing the error and is there any information on the WHS (event logs) that might give you a clue as to what the problem might be when you try to attach to it.