Hello,
I apologize, I see EraserUtilRebootDrv.sys and not EraserUtilDrv11220.sys which gets installed with SEP 12.1 RU2
Did you have any other Symantec Product OR any older Symantec product on the same machine??
When you check the properties by right clicking on the EraserUtilDrv11220.sys file, do you see any Digital Signatures Tab??
If not, could you please submit the File to the Symantec Security Response Team on https://submit.symantec.com/essential
and
http://www.threatexpert.com/submit.aspx
Note: ThreatExpert is owned by Symantec.