The remote host is vulnerable to a buffer overflow.
The remote client is running Microsoft Outlook Express. The noted version of Outlook Express is vulnerable to a buffer overflow in the way that it handles the parsing of .wab files. An attacker exploiting this flaw would need to be able to entice the user into opening the attachment. Successful exploitation would result in code being executed with the rights of the compromised user.
Upgrade or patch according to vendor recommendations.