Image Uploading and Signup Code

Here is My code for Image upload and Inserting data into Database but it is not working Properly. and also not showing any error. Tell me My Mistake where i'm wrong in this i'm bit new on PHP.Echo and Error (die) does not showing any message or error ?? what should i do ??

<?php
if(isset($_Post['submitbtn']))
{
    $target_dir = "Resources/images/users/";
    $target_file = $target_dir . basename($_FILES["fileToUpload"]["name"]);
    $uploadOk = 1;
    $imageFileType = strtolower(pathinfo($target_file,PATHINFO_EXTENSION));
    // Check if image file is a actual image or fake image
    $check = getimagesize($_FILES["fileToUpload"]["tmp_name"]);
    if($check !== false) {
        echo "File is an image - " . $check["mime"] . ".";
        $uploadOk = 1;
    } else {
        echo "File is not an image.";
        $uploadOk = 0;
    }
    if (file_exists($target_file))
    {
        echo "Sorry, file already exists.";
        $uploadOk = 0;
    }   
    if (file_exists($target_file)) 
    {
        echo "Sorry, file already exists.";
        $uploadOk = 0;
    }
    if($imageFileType != "jpg" && $imageFileType != "png" && $imageFileType != "jpeg"
    && $imageFileType != "gif" ) 
    {
        echo "Sorry, only JPG, JPEG, PNG & GIF files are allowed.";
        $uploadOk = 0;
    }
    if ($uploadOk == 0) 
    {
        echo "Sorry, your file was not uploaded.";
    // if everything is ok, try to upload file
    } 
    else 
    {
        if (move_uploaded_file($_FILES["fileToUpload"]["tmp_name"], $target_file)) 
        {
            echo "The file ". basename( $_FILES["fileToUpload"]["name"]). " has been uploaded.";
        } 
        else 
        {
            echo "Sorry, there was an error uploading your file.";
        }
    }

    $qur = "insert into users values ('"+$_Post['Id']+"','"+$_Post['firstname']+"','"+$_Post['lastname']+"','"+$_Post['email']+"','"+$_Post['Password']+"','"+'shopkeeper'+"','"+$target_file+"')";

    if(mysqli_query($con,$qur))
    {
        echo "Data Saved";
    }
    else
    {
         die("Connection failed: " . mysqli_error());
    }
}

?>