SlideShowExtender使用时出现脚本错误

[OKMZY]

我在使用SlideShowExtender的时候，老是提示错误：
Char：1
错误：'Sys' 未定义
代码：0
前台代码是：
<form id="form1" runat="server">
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<asp:Image ID="Image1" runat="server" Height="300" Width="250px"
Style="border: 1px solid black;width:auto"
ImageUrl="~/images/1.gif"
AlternateText="Blue Hills image"/>
<asp:Label runat="server" ID="imageDescription" CssClass="slideDescription"></asp:Label><br /><br />

<asp:Button runat="Server" ID="prevButton" Text="Prev" Font-Size="Larger" />
<asp:Button runat="Server" ID="playButton" Text="Play" Font-Size="Larger" />
<asp:Button runat="Server" ID="nextButton" Text="Next" Font-Size="Larger" />

<cc1:SlideShowExtender ID="SlideShowExtender1" runat="server" TargetControlID="Image1"
SlideShowServiceMethod="GetSlides"
AutoPlay="true"
ImageDescriptionLabelID="imageDescription"
NextButtonID="nextButton"
PlayButtonText="Play"
StopButtonText="Stop"
PreviousButtonID="prevButton"
PlayButtonID="playButton"
Loop="true">
</cc1:SlideShowExtender>
</form>


后台代码是：
[System.Web.Services.WebMethod]
[System.Web.Script.Services.ScriptMethod]
public static AjaxControlToolkit.Slide[] GetSlides()
{
return new AjaxControlToolkit.Slide[] {
new AjaxControlToolkit.Slide("images/1.gif", "Blue Hills", "Go Blue"),
new AjaxControlToolkit.Slide("images/2.gif", "Sunset", "Setting sun"),
new AjaxControlToolkit.Slide("images/3.gif", "Winter", "Wintery..."),
new AjaxControlToolkit.Slide("images/4.gif", "Water lillies", "Lillies in the water"),
new AjaxControlToolkit.Slide("images/5.gif", "Sedona", "Portrait style picture")};
}

我是一步步按照官方的例子去做的啊，可效果就是出不来，哪位高手帮指点一下吧。

[OKMZY]

自己解决了。。。