Hello,
What Operating System are you facing this issue on?
You might want to Look at a Symantec KB Article:
Symantec Endpoint Protection client crashes with Faulting Application Rtvscan.exe, faulting module msvcr80.dll.
I personally would recommend you to open a Web case with Symantec Tech Support:
You can log a case on web portal:
QuickStart Guide - Create and Manage Support Cases in SymWISE
http://www.symantec.com/docs/HOWTO31132
How to update a support case and upload diagnostic files with MySupport
http://www.symantec.com/docs/TECH71023
Note: Make sure you are prepared with the Full Memory Dump for Indepth Analysis along with Symantec Support Tool Log to understand the root cause.