Call to a member function fetch_assoc() on boolean
<p>I know there are other people with this error message. But there is not the answer i need.
It keeps giving me the error.. I really need to fix this.
This is my code:</p>

<pre><code>&lt;?php

if($_SERVER['REQUEST_METHOD'] == 'POST' &amp;&amp; isset($_POST['submit']))
{
$DBConnect = mysqli_connect("localhost", "root", "");
$email = mysqli_real_escape_string($DBConnect, $_POST['email']);
$wachtwoord = mysqli_real_escape_string($DBConnect, $_POST['wachtwoord']);

if(!empty($email) &amp;&amp; !empty($wachtwoord))
{
    $selectGebruiker = mysqli_query($DBConnect, "SELECT lidID, wachtwoord FROM geregistreerden WHERE email='$email'");

    while ($row = $selectGebruiker-&gt;fetch_assoc())
    {
        $email = $row['email'];
        $wachtwoordHash = $row['wachtwoord'];
    }

    $checkGebruiker = mysqli_num_rows($selectGebruiker);

    $wachtwoordCheck = password_verify ( $wachtwoord , $wachtwoordHash );

    if( $checkGebruiker &amp;&amp; $wachtwoordCheck )
    {
        $_SESSION['email'] = $email;
        echo "gelukt!!";
    }
    else
    {
        $loginError = 'Email / wachtwoord is onjuist';
        echo "Onjuist";
    }

}
else
{
    $loginError = 'Email / wachtwoord is onjuist.';
}
}
?&gt;
</code></pre>