many "(unavailable) GET" in apache logs, why? the logs like: ------------------ 52-3 - 0/0/5675 . 0.00 743 0 0.0 0.00 12.35 66.111.21.105 (unavailable) GET /1.xml HTTP/1.1 53-3 - 0/0/4336 . 0.00 742 0 0.0 0.00 10.65 69.77.94.91 (unavailable) GET /1.png HTTP/1.1 54-3 - 0/0/4099 . 0.00 742 0 0.0 0.00 8.04 69.77.94.91 (unavailable) GET /2.gif HTTP/1.1 ------------- Thanks in advance.