joomla 2.5装了中文语言包之后出现错误提示

请问各位大大，
joomla 2.5装了中文语言包之后出现错误提示
Notice: iconv() [function.iconv]: Detected an illegal character in input string in F:\PHPnow-1.5.6\vhosts\127.0.0.103\libraries\joomla\string\string.php on line 730
该怎么解决呢