I think it's possible this has nothing to do with hostname - I found this in the error_log
Code:
[Sat Apr 03 06:36:29 2010] [alert] getpwuid: couldn't determine user name from uid 4294967295, you probably need to modify the User directive
[Sat Apr 03 06:36:29 2010] [alert] getpwuid: couldn't determine user name from uid 4294967295, you probably need to modify the User directive
[Sat Apr 03 06:36:29 2010] [notice] Apache/2.2.3 (CentOS) configured -- resuming normal operations
[Sat Apr 03 06:36:29 2010] [error] mod_fcgid: fcgid process manager died, restarting the server
[Sat Apr 03 06:36:29 2010] [notice] SIGHUP received. Attempting to restart
[Sat Apr 03 06:36:29 2010] [notice] Digest: generating secret for digest authentication ...
[Sat Apr 03 06:36:29 2010] [notice] Digest: done
[Sat Apr 03 06:36:29 2010] [alert] getpwuid: couldn't determine user name from uid 4294967295, you probably need to modify the User directive
[Sat Apr 03 06:36:29 2010] [notice] mod_python: Creating 4 session mutexes based on 256 max processes and 0 max threads.
[Sat Apr 03 06:36:29 2010] [alert] getpwuid: couldn't determine user name from uid 4294967295, you probably need to modify the User directive