With so little information (we don't even know if you are in Mac or Win), I wouldn't dare to try to guess what's going on, but you can try using the full offline Reader installer from
Sorry for the lack of detail – Windows 7, trying to install Reader version 11.0.04.
I had already been to http://get.adobe.com/reader/enterprise/ and been unsuccessful. However, this time I downloaded version 9.5.0 – SUCCESS! It then updated itself to version 9.5.5.
I think that I will stick with that for the time being.