I can't imagine what Dell are trying to tell you, if you have an internet connection you should be able to download whatever you want.
What do they say you need to upgrade?
What prevents you downloading?
You only need the most recent (which is version 6 update 17). Updates don't overwrite the previous versions so you can
end up, as you have, with multiple versions installed.
If I were you I'd uninstall all of them, then download & install the current version ..... http://www.java.com/en/
These links indicate it's a recent thing with the cause not yet clear...