I'm experiencing almost the same problem.
My Build is 9.3.162, Version 9.3 (Security centre) and the DAT is 5695.
The crashing application is mcshield.exe.
Problemereignisame: APPCRASH
Anwendungsname: mcshield.exe
Anwendungsversion: 14.0.0.423
Anwendungszeitstempel: 49ad7d5b
Fehlermodulname: mscan64a.dll
Fehlermodulversion: 5.300.0.2777
Fehlermodulzeitstempel: 486bbc99
Ausnahmecode: c0000005
Ausnahmeoffset: 0000000000166de9
I'm running Vista Home. The problem surfaced after the IE 8 installation along with windows security updates. The service doesn't crash on starting several programs like Firefox, Spybot S&D, Open Office and some others. But when i try starting some programs, like Skype for example, or some older 32bit programs, it crashes. Mcshield.exe shows itself as terminated in the service list. It can be restarted manually without problems, and it doesn't fail again, until i start another (most commonly 32bit) program. I had also the problems with the "You're not protected" message, but these are gone after updating to 5695.
Several scans with Macaffee and Spybot S&D do not show an infection. The MVT is always pleased to tell me that there are no problems and everything is fine. If needed, i can provide a new session ID.
My (not very educated) guess is that there exists a problem with handling 32bit flagged applications accessing informations from the net. Eventually it is one of the security updates which changed the Microsoft killbits.
Anyway, i'm not very happy with a constantly crashing on access scanner. Unfortunately the live chat/e-mail support is no option for me, because they are both greyed out and not accessible. I'm not a pro, so i'd like to apologize if i got something wrong and i'd be glad if you can point me in the right direction, or provide some informations about solving this problem
Thanks in advance
Giu