I am trying to use ajaxtool kit downloaded from here for colorpicker.
When i tries to use this on any of my page, it shows me an error
        This page is missing a HtmlHead control which is required for the CSS
 stylesheetlink that is being added. Please add <head runat="server" />. 
What can be the reason. I am using ToolScriptManager rather than Script Manager as said in the documentation. I am using Asp.net 3.5 and using colorPicker control under a content page and adding ToolScript Manager in the same place.
As said by rafel
<head>
<title>l</title>
    <link href="<%= ResolveUrl("~/css/style.css") %>" rel="stylesheet" type="text/css" />
    <link rel="stylesheet" type="text/css" href="<%= ResolveUrl("~/css/chromestyle.css") %>"/>
    <script src="<%= ResolveUrl("~/js/JScript.js") %>" type="text/javascript"></script>
    <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.0/jquery.min.js"></script>
    <script type="text/javascript" src="<%= ResolveUrl("~/js/chrome.js") %>"></script>
    <asp:ContentPlaceHolder id="head" runat="server">
    </asp:ContentPlaceHolder>
</head>
If I adds runat in head i starts getting this error
    The Controls collection cannot be modified because the control 
contains code blocks (i.e. <% ... %>).