Corrupted uninstallation is maybe the caused
I'm using NIS 2007 and have tried removing it using Add/Remove Programs twice already to see how it will do its job in removing itself. So far, no problem.
You can try to run the Norton Removal Tool that Roddy posted earlier since your Norton failed to uninstall some old stuff. When all is done, restart then install NIS 2007 again. That is if you haven't get another security suite.