Question : Faulting application inetinfo.exe - MS Exchange goes down....

I have installed an Exchange 2003 SP2 Server on a Windows 2003 Server SP2 also&
For two days now I get this APPLICATION event :

=====================
Event Type:      Error
Event Source:      Microsoft Exchange Server
Event Category:      None
Event ID:      1000
Date:            9/4/2008
Time:            00:57:11
User:            N/A
Computer:      SRV-MAILII
Description:
Faulting application inetinfo.exe, version 6.0.3790.3959, stamp 45d69692, faulting module ntdll.dll, version 5.2.3790.3959, stamp 45d70ad8, debug? 0, fault address 0x00028235.
=====================


In the next second I get these SYSTEM events :

=====================
Event Type:      Error
Event Source:      Service Control Manager
Event Category:      None
Event ID:      7031
Date:            9/4/2008
Time:            00:57:12
User:            N/A
Computer:      SRV-MAILII
Description:
The IIS Admin Service service terminated unexpectedly.  It has done this 112 time(s).  The following corrective action will be taken in 1 milliseconds: Run the configured recovery program.
=====================

=====================
Event Type:      Error
Event Source:      Service Control Manager
Event Category:      None
Event ID:      7031
Date:            9/4/2008
Time:            00:57:12
User:            N/A
Computer:      SRV-MAILII
Description:
The Microsoft Exchange POP3 service terminated unexpectedly.  It has done this 112 time(s).  The following corrective action will be taken in 60000 milliseconds: Restart the service.
=====================
=====================
Event Type:      Error
Event Source:      Service Control Manager
Event Category:      None
Event ID:      7031
Date:            9/4/2008
Time:            00:57:12
User:            N/A
Computer:      SRV-MAILII
Description:
The Microsoft Exchange Routing Engine service terminated unexpectedly.  It has done this 112 time(s).  The following corrective action will be taken in 60000 milliseconds: Restart the service.
=====================

=====================
Event Type:      Error
Event Source:      Service Control Manager
Event Category:      None
Event ID:      7031
Date:            9/4/2008
Time:            00:57:12
User:            N/A
Computer:      SRV-MAILII
Description:
The Simple Mail Transfer Protocol (SMTP) service terminated unexpectedly.  It has done this 112 time(s).  The following corrective action will be taken in 60000 milliseconds: Restart the service.
=====================

As a result the exchange is stopping and I must restart the services. (which is done automatically)
This happens every ten to twenty minutes.
In the middle time everything works fine&
There is nothing I had installed these days.
There is a Symantec mail security for exchange server installed, Symantec antivirus and office XP.
I also had the exchange database defragged&

Thanks in advance&

Answer : Faulting application inetinfo.exe - MS Exchange goes down....

The problem disappeared by itself with no other action taken by me!
I thing, maybe it was a strange message that was pop3ed out at last&
Thanks a lot for your help!