$error = false;
if(mysql_connect()){
    if($result = mysql_query($query)){
        while($data = mysql_fetch_row($result) || !$error){
            if(is_readable($data['file'])){
                $fileContent = file_get_contents($data['file']);
                if(strpos($fileContent,'asdfg') === 0){
                    //...
                } else {
                    $error = true;
                }
            }  else {
                $error = true;
            }
        }
    } else {
        $error = true;
    }
} else {
    $error = true;
}
if($error){
    $message = 'ошибка';
} else {
    $message = 'все нормально';
}
echo $message;