Happy to see you have pinned down the problem
I have ever met the similar problem. But I did not remember ...sorry. HTTP server assumes you run a DNS. Since you don't have, you need to define ServerName.
when i started IBM HTTP Server 220.127.116.11 Administraton Service in WindowsNT4.0 sp6 .I got a error message-"Could not start the IBM HTTP Administration. Error 1067 the service terminated unexpectedly".Why?How can I do?