请问这个是从dll还是哪里找的命名空间

请问这个是从dll还是哪里找的命名空间<%@ Register TagPrefix="webdiyer" Namespace="Wuqi.Webdiyer" Assembly="AspNetPager" %>
找来找去就是没找到有Wuqi.Webdiyer这个文件.怎么办。55555555555这条语句是什么意思!谢谢大哥
完整的代码如下:
<%@ Page language="c#" Codebehind="default.aspx.cs" AutoEventWireup="false" Inherits="tmweb.WebForm2" %>
<%@ Register TagPrefix="webdiyer" Namespace="Wuqi.Webdiyer" Assembly="AspNetPager" %>
<%@ Reference Control="UserloginControl.ascx"%>
<%@ Reference Control="UserLayout.ascx"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
<HEAD>
<title>default</title>
<meta content="Microsoft Visual Studio .NET 7.1" name="GENERATOR">
<meta content="C#" name="CODE_LANGUAGE">
<meta content="JavaScript" name="vs_defaultClientScript">
<meta content="http://schemas.microsoft.com/intellisense/ie5" name="vs_targetSchema">
<LINK rev="stylesheet" media="all" href="styles/blue.css" type="text/css" rel="stylesheet">
</HEAD>
<body MS_POSITIONING="GridLayout" topmargin="0">
<form runat=server>
<asp:PlaceHolder id="PlaceHolder8" runat="server"></asp:PlaceHolder>
<table class="wordbreak" cellSpacing="6" cellPadding="4" width="768" align="center" border="0">
<tr>
<td class="TBG1" vAlign="top" noWrap width="160"><FONT face="宋体"><asp:placeholder id="PlaceHolder1" runat="server"></asp:placeholder><asp:placeholder id="PlaceHolder2" runat="server"></asp:placeholder><BR>
<asp:placeholder id="PlaceHolder3" runat="server"></asp:placeholder><asp:placeholder id="PlaceHolder4" runat="server"></asp:placeholder><asp:placeholder id="PlaceHolder5" runat="server"></asp:placeholder><asp:placeholder id="PlaceHolder6" runat="server"></asp:placeholder>
<asp:PlaceHolder id="PlaceHolder7" runat="server"></asp:PlaceHolder></FONT></td>
<td vAlign="top" width="100%">
<div id="DispContent" runat="server"></div>
<FONT face="宋体"></FONT><FONT face="宋体"></FONT><FONT face="宋体"></FONT>
<br>
<div class="content_head" align="right">
<webdiyer:AspNetPager id="AspNetPager1" runat="server" PageSize="2"></webdiyer:AspNetPager></div>
</td>
</tr>
</table>
</form>
</body>
</HTML>
上面的<asp:placeholder id="PlaceHolder3" runat="server"></asp:placeholder>从哪来的。谢谢