To disable pop-up blocking in Norton's Internet Security/Firewall, do the following:
Bring up Norton Internet Security's/Firewall's main window. This can be accomplished by opening the Windows Start menu, selecting Programs (or All Programs) and then Norton Firewall. A window like the following should appear:
Click on the Ad Blocking line.
Click on the Turn Off button.
Close the window.
Once you are finished, you can go back into the menu again to turn on the Pop-up Blocker.