Event ID 45 DFRGNTFS.EXE

I'm using SEP 12.1.4013 on WinXP Pro. Why do I get hundreds of Event ID 45 on many computers?

Here is one example taken from SEP Client event (there are hundreds of these events):

Event Type:    Information
Event Source:    Symantec AntiVirus
Event Category:    None
Event ID:    45
Date:        3/3/2014
Time:        8:00:23 AM
User:        NT AUTHORITY\SYSTEM
Computer:    DELL
Description:
 
Scan type: Tamper Protection Scan
Event: Tamper Protection Detection
Security risk detected: C:\WINDOWS\SYSTEM32\DFRGNTFS.EXE
File: C:\Program Files\Symantec\Symantec Endpoint Protection\12.1.4013.4013.105\Bin\LDVPCtls.ocx
Location: C:\Program Files\Symantec\Symantec Endpoint Protection\12.1.4013.4013.105\Bin
Computer: DELL
User: SYSTEM
Action taken: Leave Alone
Date found: Monday, March 03, 2014  8:00:23 AM

The following is taken from Application event:

Event Type:    Information
Event Source:    Symantec AntiVirus
Event Category:    None
Event ID:    45
Date:        3/4/2014
Time:        8:55:16 AM
User:        DOMAINNAME\JDOE
Computer:    DELL
Description:
 
Scan type: Tamper Protection Scan
Event: Tamper Protection Detection
Security risk detected: C:\WINDOWS\EXPLORER.EXE
File: C:\Program Files\Symantec\S32EVNT1.DLL
Location: C:\Program Files\Symantec
Computer: DELL
User: JDOE
Action taken: Leave Alone
Date found: Tuesday, March 04, 2014  8:55:16 AM

Explorer.exe is part of Windows core component. Why is it a security risk?