C# - Nullref Exc. On Label Detected By Intellisense?

the MasterPage concept and there's an error I just can't figure out.

This is a part of my default.aspx:

<asp:Content ID="ContentLoginContent" ContentPlaceHolderID="LoginContentPlaceHolder" runat="server">
<div id="ContentLoginDiv">
You've got <asp:Label ID="MemberCreditLabel" runat="server" Text="0"></asp:Label> credits.
</div>

This is the relevant part of my default.aspx.cs:

public partial class _Default : System.Web.UI.Page
{
protected void Page_Init(object sender, EventArgs e)........

What I want to do is to show a credit amount stored in a database. The function for retreiving the data I want works. I take the user name of the currently logged in user and want to get the credit amount associated with the user.