無啦啦去唔到網站

我今日無啦啦去唔到個網站, 係討論區來的!!
尋日仲去到, 今日就去唔到喇...
出現以下的字眼 :

Bad Request
Your browser sent a request that this server could not understand.
Size of a request header field exceeds server limit.


Cookie: phpbb2mysql_data=a%3A2%3A%7Bs%3A11%3A%22autologinid%22%3Bs%
..............勁大斷呢d奇怪字!!!!


--------------------------------------------------------------------------------

Apache/1.3.33 Server at shared.domain Port 80


完全唔知咩黎.....有冇人help me?????!!!!!
thx!!!!!!!!!