I had this same error occur on a different server last week. I thought it
was a WebGUI issue, because it showed up right after an upgrade. The two
servers have the same distro (CentOS 4.1), and yum running. Both worked
fine for some time, especially this latest box. It has been running for 6
months. I have not done any work on the box for a couple months now, so
whatever occurred must have been from yum. Any ideas how to fix this?

(this is not a httpd.conf issue)

root at www ~]# service httpd restart
Stopping httpd:                                            [FAILED]
Starting httpd: execvp: No such file or directory
                                                           [FAILED]