BUG: When you submit a request to an ASP page that calls a COM component in Internet IIS 6.0, you may receive an error message

When you submit a request to an Active Server Pages (ASP) page that calls a Component Object Model (COM) component in Microsoft Internet Information Services 6.0, you may receive one of the following error messages: This problem occurs when the COM component tries to create a window or set a window hook. The underlying call to the SetWindowsHookEx function fails.

You may also receive the following error message:This problem may occur even though the ASP Web application works correctly in IIS 5.0.

This problem occurs because IIS 6.0 does not enable a COM component to create a window or to set a window hook. This is a feature of IIS 6.0 that is designed to help you increase the level of security.

To resolve this problem, change the code in the application to avoid calling the SetWindowsHookEx function to create a window or to set a window hook. For example, do not use an OCX component that is designed to work in an interactive environment that uses a host window. Use non-interactive COM components instead. Microsoft Foundation Class (MFC)-based controls and libraries frequently use windows and windows hooks.

Important These steps may increase your security risk. These steps may also make your computer or your network more vulnerable to attack by malicious users or by malicious software such as viruses. We recommend the process that this article describes to enable programs to operate as they are designed to, or to implement specific program capabilities. Before you make these changes, we recommend that you evaluate the risks that are associated with implementing this process in your particular environment. If you choose to implement this process, take any appropriate additional steps to help protect your system. We recommend that you use this process only if you really require this process.

To work around this problem, run IIS 6.0 in IIS 5.0 isolation mode. To do this, follow these steps:

1. Click Start, click Run, type inetmgr, and then click OK.
2. Expand Computer Name, right-click Web Sites, and then click Properties.
   
   Note Computer Name is a placeholder for the name of your computer.
3. Click the Service tab.
4. Click to select Run WWW Service in IIS 5.0 isolation mode check box, and then click OK.

Note IIS 5.0 isolation mode is only supported by Microsoft Windows Server 2003.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.