open GL won't install (Help)

when installing open GL it comes up with a message which says
“error 26 Failed to communicate with network server”
It also goes wrong when using setup because it says that there is an old version of open GL installed and it would be recommended to download the latest edition but i only just have downloaded the latest edition and however many times i try installing it it still says the same thing.
any ideas and help will be welcome
thanks