I follow the following instruction to set up DesignitGallery

Download the codeplex package
Under Umbraco Developer section, select Packages, Install Local Package and follow the prompts.
Add a Property to your document type, Gallery as a Media Picker
Under Templates add the following lines to your template:
<%@ Master Language="C#" MasterPageFile="/masterpages/Master.master" AutoEventWireup="true" %>
<asp:content ContentPlaceHolderId="BodyContent" runat="server">
<script src="/scripts/Designit.Gallery/jquery.lightbox-05.pack.js" type="text/javascript"></script>
<script src="/scripts/Designit.Gallery/jquery.lightbox-0.5.js" type="text/javascript"></script>
<umbraco:Macro folderId="[#Gallery]" ThumbWidth="100" ThumbHeight="100" LightBoxWidth="600" LightBoxHeight="600" Alias="Designit.Gallery" runat="server"></umbraco:Macro>
<script type="text/javascript">
$(function() {
  $('#diGallery a').lightBox();
});
</script>
</asp:content>

Under Media, create a folder say "MyGallery" and add images to this folder
Under Content create a document with this document type and template
Set the property Gallery to the folder "MyGallery"
Publish and Preview
 
If I leave umbraco:Macro folderId="[#Gallery]" unchanged, the browser warmed Jquery was not defined and the particular page lacks object. If I replace #Gallery with the corresponding node ID, then it said Object reference not set to an instance of an object.  How to settle the problem? Thanks a lot!