This indicates an attack attempt against a remote file-execution vulnerability in Windows Mail.
The vulnerability is caused by the application's failure to properly check the contents of the received mail. It can be exploited via a crafted mail, leading to remote file execution.
Microsoft Windows Vista Ultimate
Microsoft Windows Vista Home Premium
Microsoft Windows Vista Home Basic
Microsoft Windows Vista Enterprise
Microsoft Windows Vista Business
System Compromise: Remote attackers can gain control of the vulnerable system.
Apply the appropriate patch from the vendor.