ASP.NET Expression is not a method
<p>I'm getting a build error, "Expression is not a method" for the following code</p>

<pre><code>Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
          'LOOKUP SKU DATA ON BLUR
          Dim lookup As String = ClientScript.GetPostBackEventReference(txtSKU, "", False)
          txtSKU.Attributes.Add("onblur", "doLookup()")

          If Not IsPostBack Then
               If txtSKU.Text &lt;&gt; "" Then
                    lookup() '*************the error points to this line*******
               End If
          End If

     End Sub

     Protected Sub btnLookup_Command(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.CommandEventArgs) Handles btnLookup.Command
          lookup()
     End Sub

     Protected Sub lookup()
          'BLAH BLAH BLAH
     End Sub
</code></pre>

<p>Any thoughts or suggestions?</p>
