On-Line Scan Error Message

 I've downloaded the Symantec On-line scan (symCCIS), but when I try to  run setup, I get the following message:

  "We cannot download this product because your system did not meet the installation  requirements or you are not logged in as an Administrator."  I am logged in as the Administrator and I even tried "Run as Administrator", but I can't get the program to install.  If my system can run NIS 19.9.1.14, I should be able to run the On-line scan, shouldn't I?  I just installed a new router and I want to make sure it is safe from prying eyes.  Is there a way to get past that error message?