This indicates an attack attempt to exploit a Buffer Overflow vulnerability in Apple QuickTime Plugin.
The vulnerability, which is located in the "QTPlugin.ocx" ActiveX control, can be exploited through misuse of the "SetLanguage" method. It may allow remote attackers to execute arbitrary code in the context of the application, using the affected ActiveX control.
QuickTime prior to 7.7.2
System Compromise: Remote attackers can execute arbitrary script code within the context of the target user's browser
Apply the most recent upgrade or patch from the vendor