SAV 8 is end-of-life and no longer gets new definitions. Knowing this really makes me think your system is infected. You need to upgrade your AV solution ASAP.
Symantec Antivirus 8.0 reached its End of Support Life as of November 30, 2005 and Symantec Antivirus 8.1 reached its End of Support Life as of January 31, 2007, as defined in the Symantec Enterprise Technical Support Policy. Therefore virus definition updates are no longer supported for this product.
http://www.symantec.com/business/security_response/definitions/download/detail.jsp?gid=savce