You don't say what you're doing to get this download or what operating system you're using.
Turn off your antivirus and firewall. (If it's Norton, you may want to get a different antivirus program)
Make sure you're running Premiere Elements as an administrator
Go to the program's Help menu and select Check for Updates
If that fails, uninstall the program, run CCleaner (a free download) and then reinstall the program and try again.
BTW, do you have other versions of Premiere Elements on your computer?