ASP.NET MVC Client Side Validation Message Error

Question

Can somebody tell me why "This field is required" and "Please insert database name" are being displayed instead of just "Please insert database name"?

This is my model :

public class InstallViewModel
    {
        [Required(AllowEmptyStrings = false, ErrorMessage = "Please insert database name")]
        public string DatabaseName { get; set; }

and this is my view :

<div class="input-group">
    <span class="input-group-addon">Database</span>
    @Html.TextBoxFor(w => w.DatabaseName, new { @class = "form-control", placeholder = "Database name" })
</div>
@Html.ValidationMessageFor(w=> w.DatabaseName)

Thank you.

EDIT:

Can you see the image attached ? I have some problems uploading images.

The view is a partial view and this is the whole partial view:

@Html.ValidationMessageFor(w => w.DatabaseName)
    <div class="input-group">
        <span class="input-group-addon">Database</span>
        @Html.TextBoxFor(w => w.DatabaseName, new { @class = "form-control", placeholder = "Database name" })
    </div> 
    <br />
    @Html.CheckBoxFor(w => w.UseWindowsAuthentication, new { @checked = "checked" }) Use Windows Authentication<br /><br />
    <div class="wizard-sqlauth" style="display: none">
        <div class="input-group">
            <span class="input-group-addon">User name</span>
            @Html.TextBoxFor(w => w.UserName, new { @class = "form-control", placeholder = "User name" })
        </div>
        @Html.ValidationMessageFor(w => w.UserName)<br />
        <div class="input-group">
            <span class="input-group-addon">Password</span>
            @Html.PasswordFor(w => w.Password, new { @class = "form-control" })
        </div>
        @Html.ValidationMessageFor(w => w.Password)
    </div>

Answer 1

DatabaseName is "Required" and your input is empty. (There is only placeholder text)