安装1.5出错

安装时输入数据库配置后点击安装按钮报以下错误：
Warning: Illegal string offset 'dbhost' in C:\df\install\index.php on line 161

Warning: Illegal string offset 'dbname' in C:\df\install\index.php on line 164

Warning: Illegal string offset 'dbuser' in C:\df\install\index.php on line 167

Warning: Illegal string offset 'dbpass' in C:\df\install\index.php on line 170

Warning: Illegal string offset 'prefix' in C:\df\install\index.php on line 173