This indicates an attack attempt to exploit a vulnerability in the Stack Structure of Internet Explorer.
The vulnerability is in the Internet Explorer scripting engines, both VBscript and Jscript. It can be exploited by calling an infinite recursive function that may lead to a Denial of Service condition.
Microsoft Internet Explorer 6.0 SP1
Microsoft Internet Explorer 6.0
Denial of Service: Remote attackers can crash vulnerable systems.
Update to Microsoft Internet Explorer 7.0 or later.