Lighttpd

I'm running lighttpd on my ubuntu 7.10 box. My website is file hosting that send file via x-sendfile. I've some problem about async-read that NULL bytes appears in downloader in sometime.

network_linux_aio.c.67: (trace) async-read failed with -14 (Bad address), was asked for /404.php (fd = 1409)
network_linux_aio.c.67: (trace) async-read failed with -14 (Bad address), was asked for /404.php (fd = 717)
network_linux_aio.c.67: (trace) async-read failed with -14 (Bad address), was asked for /404.php (fd = 742)
network_linux_aio.c.67: (trace) async-read failed with -14 (Bad address), was asked for /404.php (fd = 1402)
network_linux_aio.c.67: (trace) async-read failed with -14 (Bad address), was asked for /404.php (fd = 778)
network_linux_aio.c.67: (trace) async-read failed with -14 (Bad address), was asked for /404.php (fd = 298)
network_linux_aio.c.67: (trace) async-read failed with -14 (Bad address), was asked for /404.php (fd = 781)
network_linux_aio.c.67: (trace) async-read failed with -14 (Bad address), was asked for /404.php (fd = 77)
network_linux_aio.c.67: (trace) async-read failed with -14 (Bad address), was asked for /404.php (fd = 628)
network_linux_aio.c.67: (trace) async-read failed with -14 (Bad address), was asked for /404.php (fd = 103)
network_linux_aio.c.67: (trace) async-read failed with -14 (Bad address), was asked for /404.php (fd = 435)
network_linux_aio.c.67: (trace) async-read failed with -14 (Bad address), was asked for /404.php (fd = 334)
network_linux_aio.c.67: (trace) async-read failed with -14 (Bad address), was asked for /404.php (fd = 1318)
network_linux_aio.c.67: (trace) async-read failed with -14 (Bad address), was asked for /404.php (fd = 335)
network_linux_aio.c.67: (trace) async-read failed with -14 (Bad address), was asked for /404.php (fd = 337)
network_linux_aio.c.67: (trace) async-read failed with -14 (Bad address), was asked for /404.php (fd = 345)
network_linux_aio.c.67: (trace) async-read failed with -14 (Bad address), was asked for /404.php (fd = 320)
network_linux_aio.c.67: (trace) async-read failed with -14 (Bad address), was asked for /404.php (fd = 796)