检查apache日志发现有以下错误：
No such file or directory: exec of '/usr/local/smokeping/htdocs/smokeping.cgi' failed
[Wed Sep 05 19:48:47 2012] [error] [client x.x.x.x] Premature end of script headers: smokeping.cgi
安装perl-CGI-SpeedyCGI后，重启apache,smokeping后解决
yum -y install perl-CGI-SpeedyCGI