Download the netsweeper certificate by pressing the above "Download" button. Once downloaded, click the download and select "Open" if prompted.
Click "Install Certificate..."
Select "Local Machine" then "Next"
Check the "Place all certificates in the following store" radio button and click "Browse". When the new window appears, select "Trusted Root Certification Authorities" and click "OK".
Click "Next".
Click "OK" and "OK". You are now finished installing the certificate.