[Zope] "manage" screens don't appear on local workstation for Win2000

I just moved my Zope installation to Windows 2000. Now when I try to use any management screens, I get the default index_html pages instead. So I can't change anything or develop content. I can still access the management screens from a separate computer, but I need to work on my own machine, the one that Zope is running on. Zope is running as a service, by the way. Same result with both Zope 2.2.6 and 2.3.0, even with a completely fresh clean installation. I had no problems like this on an NT4 server. I'm out of ideas - anyone have a solution? Tom Passin