This could be 1 of 2 things:

You do not have administrator rights on your PC. In order to install any software or content on your PC, you must have administrative rights on your PC. Make sure that you are currently logged on as a user with Administrator rights and then try the update process again.

Your Firewall or security settings are blocking the content from being downloaded. Please check to make sure your firewall and security settings will allow for the download of content, and then try the update process again.