AjaxToolKit Problem - Sys error

I have meet this problem for a few project, this problem follow me long times already.
When i use the AjaxToolkit, there are totally no function in my web site.
Today i take some times to solve this problem. I try to find the solution from site. Luckily i found a solution from a site. It say is the web.config problem. I try to open a new web site, and choose that ajax enable web site. Then i compare the web.config file with empty site. I have add this few line. (blue color word) in the web.config, and my work have been work ! ^^

<configuration xmlns="http://schemas.microsoft.com/.NetConfiguration/v2.0">

<configSections>
<sectionGroup name="system.web.extensions" type="System.Web.Configuration.SystemWebExtensionsSectionGroup, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35">
<sectionGroup name="scripting" type="System.Web.Configuration.ScriptingSectionGroup, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35">
<section name="scriptResourceHandler" type="System.Web.Configuration.ScriptingScriptResourceHandlerSection, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" requirePermission="false" allowDefinition="MachineToApplication"/>
<sectionGroup name="webServices" type="System.Web.Configuration.ScriptingWebServicesSectionGroup, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35">
<section name="jsonSerialization" type="System.Web.Configuration.ScriptingJsonSerializationSection, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" requirePermission="false" allowDefinition="Everywhere"/>
<section name="profileService" type="System.Web.Configuration.ScriptingProfileServiceSection, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" requirePermission="false" allowDefinition="MachineToApplication"/>
<section name="authenticationService" type="System.Web.Configuration.ScriptingAuthenticationServiceSection, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" requirePermission="false" allowDefinition="MachineToApplication"/>
</sectionGroup>
</sectionGroup>
</sectionGroup>

<section name="SubSonicService" type="SubSonic.SubSonicSection, SubSonic" requirePermission="false"/>
<section name="rewriter" type="Intelligencia.UrlRewriter.Configuration.RewriterConfigurationSectionHandler, Intelligencia.UrlRewriter" requirePermission="false"/>
</configSections>
<connectionStrings>
<add name="CelcomFulfillment"
connectionString="Data Source=.;AttachDbFilename=d:\projects\celcomfulfillment\web\app_data\celcomfulfillment.mdf;Integrated Security=True;User Instance=True"
providerName="System.Data.SqlClient" />
</connectionStrings>
<system.net>
<mailSettings>
<smtp>
<network host="mail.spanlogic.com" port="2525" userName="testing@spanlogic.com" password="testing*88"/>
</smtp>
</mailSettings>
</system.net>
<appSettings>
<add key="RegForm:MailTo" value="yeecheing.seah@spanlogic.com"/>
</appSettings>
<system.web>
<authentication mode="Forms">
<forms loginUrl="~/spanlogicacl/signin.aspx" timeout="30"></forms>
</authentication>

<pages>
<controls>
<add tagPrefix="ajax" namespace="System.Web.UI"
assembly="System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
</controls>
</pages>

<compilation debug="true">

<assemblies>
<add assembly="System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
<add assembly="System.Design, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A"/>
<add assembly="System.Web.Extensions.Design, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
<add assembly="System.Windows.Forms, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/>
<add assembly="System.Data.OracleClient, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/></assemblies>
</compilation>
<httpHandlers>
<remove verb="*" path="*.asmx"/>
<add verb="*" path="*.asmx" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
<add verb="*" path="*_AppService.axd" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
<add verb="GET,HEAD" path="ScriptResource.axd" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" validate="false"/>
</httpHandlers>
<httpModules>
<add name="ScriptModule" type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
</httpModules>

<membership defaultProvider="AspNetSqlMembershipProvider">
<providers>
<clear/>
<add name="AspNetSqlMembershipProvider"
type="System.Web.Security.SqlMembershipProvider, System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"
connectionStringName="CelcomFulfillment"
applicationName="/"
enablePasswordReset="true"
enablePasswordRetrieval="true"
maxInvalidPasswordAttempts="10"
minRequiredPasswordLength="6"
minRequiredNonalphanumericCharacters="0"
passwordAttemptWindow="10"
passwordStrengthRegularExpression=""
passwordFormat="Clear"
requiresQuestionAndAnswer="false"
requiresUniqueEmail="false"/>
</providers>
</membership>
<roleManager enabled="true" defaultProvider="SqlRoleProvider">
<providers>
<clear/>
<add name="SqlRoleProvider" type="System.Web.Security.SqlRoleProvider"
connectionStringName="CelcomFulfillment" applicationName="/"/>
</providers>
</roleManager>
</system.web>

<system.web.extensions>
<scripting>
<webServices>
<!-- Uncomment this line to customize maxJsonLength and add a custom converter -->
<!--
<jsonSerialization maxJsonLength="500">
<converters>
<add name="ConvertMe" type="Acme.SubAcme.ConvertMeTypeConverter"/>
</converters>
</jsonSerialization>
-->
<!-- Uncomment this line to enable the authentication service. Include requireSSL="true" if appropriate. -->
<!--
<authenticationService enabled="true" requireSSL = "true|false"/>
-->
<!-- Uncomment these lines to enable the profile service. To allow profile properties to be retrieved
and modified in ASP.NET AJAX applications, you need to add each property name to the readAccessProperties and
writeAccessProperties attributes. -->
<!--
<profileService enabled="true"
readAccessProperties="propertyname1,propertyname2"
writeAccessProperties="propertyname1,propertyname2" />
-->
</webServices>
<!--
<scriptResourceHandler enableCompression="true" enableCaching="true" />
-->
</scripting>
</system.web.extensions>
<system.webServer>
<validation validateIntegratedModeConfiguration="false"/>
<modules>
<add name="ScriptModule" preCondition="integratedMode" type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
</modules>
<handlers>
<remove name="WebServiceHandlerFactory-Integrated"/>
<add name="ScriptHandlerFactory" verb="*" path="*.asmx" preCondition="integratedMode" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
<add name="ScriptHandlerFactoryAppServices" verb="*" path="*_AppService.axd" preCondition="integratedMode" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
<add name="ScriptResource" preCondition="integratedMode" verb="GET,HEAD" path="ScriptResource.axd" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
</handlers>
</system.webServer>

<SubSonicService defaultProvider="CelcomFulfillment">
<providers>
<clear/>
<!--<add name="SpanlogicComAcl"
type="SubSonic.SqlDataProvider, SubSonic"
connectionStringName="SpanlogicComAclConnectionString"
generatedNamespace="SpanlogicComAcl.Lib"
setPropertyDefaultsFromDatabase="true"
generateODSControllers="true"/>-->


<add name="CelcomFulfillment"
type="SubSonic.SqlDataProvider, SubSonic"
connectionStringName="CelcomFulfillment"
generatedNamespace="CelcomFulfillment.Lib"
setPropertyDefaultsFromDatabase="true"
generateODSControllers="true"/>
</providers>
</SubSonicService>
</configuration>