This indicates an attack attempt against a buffer-overrun vulnerability in Microsoft Office.
The vulnerability is caused by an error when the vulnerable software handles a specially crafted CGM image file. It allows a remote attacker to execute arbitrary code.
Microsoft Office XP Service Pack 3
Microsoft Office 2003 Service Pack 3
Microsoft Office Converter Pack
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the patch supplied by the vendor: