Dear Sir,
When i try to download DIAView v2.6.0, There is always show me error "404 Not Found"
Maybe the server has a temporary failure.
You also can download it from DELTA official website:
http://www.deltaww.com/services/DownloadCenter2.aspx?secID=8&pid=2&tid=0&CID=06&itemID=060701&typeID=1&downloadID=DIAView&title=DIAView&dataType=1;2;8;&check=1&hl=en-US