Thank you for your post.
I don't have a clear idea why this isn't working. This is definitely a supported operating system.
I would first uninstall FileMaker Server, stop all non-Microsoft services and reboot the server. Once rebooted, then reinstall FileMaker Server and start again.
Yes, Instant Web Publishing is not available with FileMaker Server. Only FileMaker Server Advanced.
<!-- StartFragment -->Mike,
After some research I found that Pcwum.dll is a new Windows components that can only exist on Windows Server 2008 R2 (which is currently in BETA) and Windows 7.
The above versions are not currently supported by FileMaker Server 10.
Please refer to the following URL for the system requirements for FileMaker Server 10