为什么我的openwebmail无法打开?

在客户端XP浏览http://mail.michael.com/cgi-bin/openwebmail/openwebmail.pl出错Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.
Please contact the server administrator, root@michael.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.
More information about this error may be available in the server error log.
Apache/2.2.3 (Red Hat) Server at mail.michael.com Port 80
看日志tail -f /var/log/httpd/error_log错误提示如下:
 [root@server1 ~]# tail /var/log/httpd/error_log
[Fri Mar 04 20:14:00 2011] [notice] mod_bw : Memory Allocated 168 bytes (each conf takes 28 bytes)
[Fri Mar 04 20:14:00 2011] [notice] mod_bw : Version 0.8 - Initialized [6 Confs]
[Fri Mar 04 20:14:00 2011] [notice] Apache/2.2.3 (Red Hat) configured -- resuming normal operations
[Fri Mar 04 20:17:14 2011] [notice] caught SIGTERM, shutting down
[Fri Mar 04 20:17:15 2011] [notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Fri Mar 04 20:17:15 2011] [notice] Digest: generating secret for digest authentication ...
[Fri Mar 04 20:17:15 2011] [notice] Digest: done
[Fri Mar 04 20:17:15 2011] [notice] mod_bw : Memory Allocated 168 bytes (each conf takes 28 bytes)
[Fri Mar 04 20:17:15 2011] [notice] mod_bw : Version 0.8 - Initialized [6 Confs]
[Fri Mar 04 20:17:15 2011] [notice] Apache/2.2.3 (Red Hat) configured -- resuming normal operations