erros no antivirus

galera.. ta dando o seguinte erro nos logs do antivirus:

scanmails[27991]: WARNING! Don't know how to handle y15381.0.EXE (no unrar)
scanmails[27991]: WARNING! Don't know how to handle y15518.0.EXE (no unrar)
]: WARNING! Don't know how to handle y15543.0.EXE (no unrar)
scanmails[690]: WARNING! Don't know how to handle y29068.0.EXE (no unrar)
scanmails[690]: WARNING! Don't know how to handle y29298.0.EXE (no unrar)
scanmails[690]: WARNING! Don't know how to handle y29348.0.EXE (no unrar)

o que será que pode ser?