Object Not Set Error?

Hi,
I have an update command to update a column by '1' on click.
I am getting the error:
Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.
It doesnt give which code it reffers to but the stack trace is:
[NullReferenceException: Object reference not set to an instance of an object.]
Buyers_MyPurchases.Button1_Click(Object sender, EventArgs e) +165
System.Web.UI.WebControls.Button.OnClick(EventArgs e) +75
System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +97
System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +7
System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +11
System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +33
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +4886 My code is: protected void Button1_Click(object sender, EventArgs e)
{
SqlConnection con = new SqlConnection();
con.ConnectionString = "Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\ASPNETDB.MDF;Integrated Security=True;User Instance=True";


con.Open();

SqlCommand command = new SqlCommand();
command.Connection = con;
Label productIDLabel = (Label)DataList1.FindControl("productIDLabel");

command.CommandText = "UPDATE Items SET numberclickedin = numberclickedin + 1 WHERE productID=@productID";
command.Parameters.Add("@productID", productIDLabel.Text);
command.ExecuteNonQuery();

con.Close();
command.Dispose();
} Thanks if someone can spot the issue!Jon