Sorry, it is hard to me translate it to English.
But I think it is the same to English version of Windows live mail 2009.

I have to uninstall AIS 5.1.889 and install AIS 6.0.1000. It is the same happen.

Did it possible cause by the new definition update ?

Is it possible to restore the definition back to 2 days ago ?

Also, could you post the AIS 5.1.889 download link ? (Avast Internet Security)

Thanks!