apache 错误日志信息

大家好,下面是apache下error_log文件中的错误信息：有人知道是怎么回事吗？谢谢先！
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[Wed Apr 25 18:06:34 2007] [error] (70007)The timeout specified has expired: ajp_ilink_receive() can't receive header
[Wed Apr 25 18:06:34 2007] [error] ajp_read_header: ajp_ilink_receive failed
[Wed Apr 25 18:06:34 2007] [error] (120006)APR does not understand this error code: proxy: read response failed from 127.0.0.1:8049 (localhost)
[Wed Apr 25 18:06:34 2007] [error] (70007)The timeout specified has expired: ajp_ilink_receive() can't receive header
[Wed Apr 25 18:06:34 2007] [error] ajp_read_header: ajp_ilink_receive failed
[Wed Apr 25 18:06:34 2007] [error] (120006)APR does not understand this error code: proxy: read response failed from (null) (localhost)
[Wed Apr 25 18:06:35 2007] [error] (70007)The timeout specified has expired: ajp_ilink_receive() can't receive header
[Wed Apr 25 18:06:35 2007] [error] ajp_read_header: ajp_ilink_receive failed
[Wed Apr 25 18:06:35 2007] [error] (120006)APR does not understand this error code: proxy: read response failed from (null) (localhost)
[Wed Apr 25 18:06:36 2007] [error] (70007)The timeout specified has expired: ajp_ilink_receive() can't receive header
[Wed Apr 25 18:06:36 2007] [error] ajp_read_header: ajp_ilink_receive failed
[Wed Apr 25 18:06:36 2007] [error] (120006)APR does not understand this error code: proxy: read response failed from (null) (localhost)
[Wed Apr 25 18:06:36 2007] [error] (70007)The timeout specified has expired: ajp_ilink_receive() can't receive header
[Wed Apr 25 18:06:36 2007] [error] ajp_read_header: ajp_ilink_receive failed
[Wed Apr 25 18:06:36 2007] [error] (120006)APR does not understand this error code: proxy: read response failed from 127.0.0.1:8049 (localhost)
[Wed Apr 25 18:06:39 2007] [error] [client 218.92.149.97] File does not exist: /export/home/apache/httpd223/htdocs/favicon.ico
[Wed Apr 25 18:06:41 2007] [error] (70007)The timeout specified has expired: ajp_ilink_receive() can't receive header
[Wed Apr 25 18:06:41 2007] [error] ajp_read_header: ajp_ilink_receive failed
[Wed Apr 25 18:06:41 2007] [error] (120006)APR does not understand this error code: proxy: read response failed from (null) (localhost)
[Wed Apr 25 18:06:41 2007] [error] (70007)The timeout specified has expired: ajp_ilink_receive() can't receive header
[Wed Apr 25 18:06:41 2007] [error] ajp_read_header: ajp_ilink_receive failed
[Wed Apr 25 18:06:41 2007] [error] (120006)APR does not understand this error code: proxy: read response failed from (null) (localhost)
[Wed Apr 25 18:06:41 2007] [error] (70007)The timeout specified has expired: ajp_ilink_receive() can't receive header
[Wed Apr 25 18:06:41 2007] [error] (70007)The timeout specified has expired: ajp_ilink_receive() can't receive header
[Wed Apr 25 18:06:41 2007] [error] ajp_read_header: ajp_ilink_receive failed
[Wed Apr 25 18:06:41 2007] [error] (120006)APR does not understand this error code: proxy: read response failed from (null) (localhost)
[Wed Apr 25 18:06:41 2007] [error] ajp_read_header: ajp_ilink_receive failed
[Wed Apr 25 18:06:41 2007] [error] (120006)APR does not understand this error code: proxy: read response failed from (null) (localhost)