If you continue to experience problems with the installation program failing, you are probably using a PROXY server which has saved an incomplete copy of the installation file. You need to override this setting to download a full copy from our actual web site.
To do this using Internet Explorer...
1. Go to the Connection tab in the Internet Options drop-down menu (View | Internet Options).
2. Un-check the access the Internet using a proxy server box, then try downloading again (remember to re-check the box when you're done).