This indicates an attack attempt against a memory-corruption vulnerability in Windows Internet Explorer.
The vulnerability is caused by an error when the vulnerable software handles a web page that contains an object that has not been properly initialized or has been deleted. It allows remote attackers to execute arbitrary code on vulnerable systems via sending a crafted web page.
Internet Explorer 6 for Windows XP Service Pack 3
Internet Explorer 6 for Windows XP Professional x64 Edition Service Pack 2
Internet Explorer 6 for Windows Server 2003 Service Pack 2
Internet Explorer 6 for Windows Server 2003 x64 Edition Service Pack 2
Internet Explorer 6 for Windows Server 2003 with SP2 for Itanium-based Systems
System Compromise: Remote attackers can gain control of vulnerable systems.
Refer to the wendor's website for the suggested workaround: