This indicates an attack attempt against a remote Denial of Service vulnerability in Apple's Safari for Windows web browser.
If a legitimate user can be enticed to access a specially crafted web page, the Safari web browser will crash.
Apple Safari 3.0.3 Beta for Windows
Apple Safari 3.0.2 Beta for Windows
Apple Safari 3.0.1 Beta for Windows
Apple Safari 3 Beta for Windows
Denial of Service: Remote attackers can crash vulnerable systems.
Apply patch, available from the web site.