Are you running OS X Client or OS X Server? Are you running 10.2?
Try running this command:
% cat /etc/httpd/httpd.conf | grep WebObjects
It looks to me like your config file is trying to load something that should be installed with WebObjects. For me, I don't have WebObjects and am running OS X Client. When I run the above command I get no output, meaning I have no lines in my config file with "WebObjects" in it.
If you do, but you have not installed WebObjects, you might want to edit your config file and remove that line.