Error messages in ap_get_scoreboard_lb are reported with httpd's graceful/reload

Issue

• The following error messages were reported when our customer restarted httpd with graceful after he added mod_proxy/mod_cache configurations into /etc/httpd/conf.d directory.
• The messages were also reported with httpd's reload but they were not reported with httpd's restart(stop and start).

  [Fri Nov 16 14:42:56 2012] [error] proxy: ap_get_scoreboard_lb(54) failed in child 5113 for worker http://10.13.85.238:18081/
  [Fri Nov 16 14:42:56 2012] [error] proxy: ap_get_scoreboard_lb(56) failed in child 5113 for worker proxy:reverse
  [Fri Nov 16 14:42:56 2012] [error] proxy: ap_get_scoreboard_lb(55) failed in child 5113 for worker http://10.13.85.238:18080/
  [Fri Nov 16 14:42:56 2012] [error] proxy: ap_get_scoreboard_lb(47) failed in child 5113 for worker http://10.13.88.66/listcnd/
  [Fri Nov 16 14:42:56 2012] [error] proxy: ap_get_scoreboard_lb(48) failed in child 5113 for worker http://10.13.88.66/mktpt/
  [Fri Nov 16 14:42:56 2012] [error] proxy: ap_get_scoreboard_lb(49) failed in child 5113 for worker http://10.13.88.66/kikan/
  [Fri Nov 16 14:42:56 2012] [error] proxy: ap_get_scoreboard_lb(50) failed in child 5113 for worker http://10.13.88.67/english/
  [Fri Nov 16 14:42:56 2012] [error] proxy: ap_get_scoreboard_lb(51) failed in child 5113 for worker http://10.13.88.67/cn/
  [Fri Nov 16 14:42:56 2012] [error] proxy: ap_get_scoreboard_lb(52) failed in child 5113 for worker http://10.13.88.67/kr/
  [Fri Nov 16 14:42:56 2012] [error] proxy: ap_get_scoreboard_lb(53) failed in child 5113 for worker http://10.13.88.65/