PHP 注册从不工作 - mysqli->query.

 <?php
include('connect.php');

    if (isset($_POST['username']) && isset($_POST['password'])){
        $username = $_POST['username'];
        $email = $_POST['email'];
        $password = $_POST['password'];
        global $mysqli;
        $query = ("INSERT INTO lr (username, password, email) VALUES ('$username', '$password', '$email')");
        $result = $mysqli->query($query, $connection) or die(mysql_erorr());
        if($result === true){
            $msg = "User Created Successfully.";
        }
    }

  ?>

目录：

<form id="RegisterUserForm" action="" method="post" enctype="multipart/form-data">
    <fieldset>
         <p>
            <label for="name">Name</label>
            <input id="name" name="name" type="text" class="text" value="" />
         </p>
         <p>
            <label for="tel">Email</label>
            <input id="email" name="email" type="email"  value="" />
         </p>
         <p>
            <label for="Username">Username</label>
            <input id="username" name="username" type="username"  value="" />
         </p>
         <p>
            <label for="email">Password</label>
            <input id="password" type="password" name="password"  class="text" value="" />
         </p>
         <p>
            <label for="Cpassword">Confirm Password</label>
            <input id="Cpassword" name="Cpassword" class="text" type="password" />
         </p>
         <p>
            <label for="acceptTerms">
                I agree to the <a href="">Terms and Conditions</a> and <a href="">Privacy Policy</a><br/>
                <input id="acceptTerms" name="acceptTerms" type="checkbox" />
            </label>
         </p>
        <p>
                    Upload a picture of your student ID. This is for your own safety from fraud attempts

    <input type="file" name="fileToUpload" id="fileToUpload" style="color:green">
     <input type="submit" value="Upload Image" name="submit" style="color:green">
     <br/><br/><br/> 
        </p>
          <input type="submit" id="registerNew" value="Register" />
    </fieldset>

  ad
 </form> 

这是我的代码，当我单击注册按钮时，它给了我这个错误

" 致命错误：在第 112 行的 C：''wamp''www''Unnamed Site 2''Signup.php 中对非对象调用成员函数 query（） "

我仍然是这个PHP东西的新手，需要帮助

同样，当我尝试通过DREAMWEAVER连接我的DATBASE时，它给了我一个ERROY说没有DTATABASES ABAILABE的ERROY

提前致谢