The file permissions are wrong! Your current page (and maybe some other files) are not readable by the owner (255). If your webserver is still the owner of the files, you can try the following php-script to reset the file permissions:
$path = "absolute path to your dokuwiki installations directory"; // look into the webhoster's manual
$filemode = 0755; // or something other, but don't forget the leading "0" for octal numbers
chmod_R($path, $filemode);
function chmod_R($path, $filemode) {
chmod($path, $filemode);
$dh = opendir($path);
while ($file = readdir($dh)) {
if($file != '.' && $file != '..') {
$fullpath = $path.'/'.$file;
echo $fullpath."<br/>";
if(!is_dir($fullpath)) {
chmod($fullpath, $filemode);
} else {
chmod_R($fullpath, $filemode);
}
}
}
closedir($dh);
}
This script tries to change the rights of a folder recursively, if the server is owner of the files and folders. Maybe you should try that with your datadir directly...