Hello,
The main SEP 12.1.3 download definitions page, at
http://www.symantec.com/security_response/definitions.jsp
shows current definitions and dates. When you click on the Definitions link on the "File-Based Protection" section of the SEPM 12.1.3 "Virus Definitions & Security Updates" page, you are directed to the "Symantec Endpoint Protection / Symantec Antivirus Corporate Edition" page at:
http://www.symantec.com/security_response/definitions/download/detail.jsp?gid=savce
This page appears to be stuck in the past - it displays definition Creation Dates of 03/31/2014, and invalid definition file download links.
There does not seem to be an obvious way to communicate this to Symantec without a business support account. If there is one, I apologize.