When running LiveUpdate, you are prompted for a registration key. As a corporate customer, you do not have a registration key, and did not think a registration key was required. You want to know what to do next.
Norton AntiVirus, which requires a yearly registration renewal, is installed or was installed previously on this machine. This can be verified via the QuickMenu, if the QuickMenu displays Norton Antivirus instead of Symantec AntiVirus.
Download the most current build of Symantec Antivirus Corporate Edition for Macintosh, which does not require the use of a registration key. Norton AntiVirus must be uninstalled prior to the installation of Symantec AntiVirus. If you still encounter difficulties in installation, you may want to use RemoveSymantecMacFiles to clear out remnants of the older installation.
References Norton AntiVirus can mean either the consumer edition or an older corporate edition.