This indicates an attack attempt against a stack-based buffer-overflow vulnerability in Microsoft HTML Help Workshop.
The vulnerability is caused by an error when the vulnerable software handles
a malicious ".hhp" file with too long "OPTIONS" fields. It allows a remote attacker to execute arbitrary code via sending a crafted ".hhp" file.
Microsoft HTML Help Workshop 4.74.8702.0 and earlier versions.
System Compromise: Remote attackers can gain control of vulnerable systems.
Upgrade to a non-vulnerable version.