: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.
1. If the registry key below contains any of the values indicated in part 1 of the CAUSE section above, use the Registry editor (regedt32.exe is recommended for this purpose) to delete the Filter DLLs value from the following registry key:
2. If the properties of the Default Web Site, ISAPI Filters tab indicate that another ISAPI filter is loaded ahead of the w3proxy filter and the w3proxy filter is not initializing (indicated by a red down arrow status) then:
a. Move the w3proxy filter to the top of the load order by highlighting it and using the up arrow to the left of the ISAPI filters list window so that it is at the top of the load order.
b. Apply the change to the Default Web Site by clicking the apply button at the bottom of the property sheet and then the OK button. Close the Internet Service Manager (ISM) Microsoft Management Console (MMC.)
c. Stop the following services using the Control Panel Services applet:
(1) Microsoft Proxy Server Administration service.
(2) Microsoft WinSock Proxy service.
(3) The IISAdmin service.
(4) The Proxy Alert Notification Service (if not already stopped by step 2.c.(1) above.)
(5) The World Wide Web Publishing service (if not already stopped by step 2.c.3 above.)
d. Restart the services stopped in 2.c. above.
e. Reopen the ISM MMC and expand to expose the Defalt Web Site. Right click on the Default Web Site then select Properties. Go to the ISAPI filters tab. Verify that the w3proxy has initialized properly as indicated by a green up arrow status and that it is the first ISAPI filter loaded for the Default Web Site.
f. If the w3proxy ISAPI filter did not initialize and there are other filters beings loaded on the Default Web Site, remove them (record each one and the filter's location on the server before removing) one at a time and repeat steps 2.c through 2.f. until only the w3proxy filter is being loaded.
g. Replace the filters removed earlier (if applicable) one at a time with updated versions and repeat steps 2.a. to 2.e. to test whether the updated versions work properly with the w3proxy ISAPI filter.
3. If the w3proxy ISAPI filter is at the top of the filter order and is not loading and initializing properly when the IIS 4.0 and Proxy Server 2.0 services are started, replace w3proxy.dll with a new copy from an appropriate source: Windows NT Option Pack, Small Business Server 4.5 distribution CDs, Back Office 4.5 distribution CDs or other known good source and repeat steps 2.a. through 2.g. as appropriate.
Reapply the NT 4.0 Service pack installed on the server after replacing files on the server as a precaution against having mis-matched versions on the server.