خطا "Sections must only appear once per config file. See the help topic <location> for exceptions."

[karimi84]

"Sections must only appear once per config file. See the help topic <location> for exceptions.
"
web.con من به شکل ذیل می باشد موقع اجرا پیغام خطا بالا را می دهد لطفا راهنمائی کنید

<?xml version="1.0"?>
<configuration>
<system.webServer>
<handlers>
<remove name="ChartImageHandler"/>
<add name="ChartImageHandler" preCondition="integratedMode" verb="GET,HEAD,POST" path="ChartImg.axd" type="System.Web.UI.DataVisualization.Charting.ChartHttp Handler, System.Web.DataVisualization, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
</handlers>
</system.webServer>
<appSettings>
<add key="helpdesk" value="1"/>
<add key="ChartImageHandler" value="storage=file;timeout=20;dir=c:\TempImageFiles\;"/>
</appSettings>
<connectionStrings>
<add name="HelpDeskConnectionString" connectionString="Data Source = cablebuilder;Initial Catalog=HelpDesk;Persist Security Info=True;User ID=HelpDesk_Admin;Password=_HelpAWCDesk_305" providerName="System.Data.SqlClient"/>
</connectionStrings>
<system.web>
<!--
Set compilation debug="true" to insert debugging
symbols into the compiled page. Because this
affects performance, set this value to true only
during development.
-->
<httpHandlers>
<add path="ChartImg.axd" verb="GET,HEAD,POST" type="System.Web.UI.DataVisualization.Charting.ChartHttp Handler, System.Web.DataVisualization, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" validate="false"/>
</httpHandlers>
<authorization>
<deny users="karimi"/>
</authorization>
<compilation debug="true" targetFramework="4.0">
<assemblies>
<add assembly="System.Web.DataVisualization, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/></assemblies>
</compilation>
<!--
The <authentication> section enables configuration
of the security authentication mode used by
ASP.NET to identify an incoming user.
-->
<!--
The <customErrors> section enables configuration
of what to do if/when an unhandled error occurs
during the execution of a request. Specifically,
it enables developers to configure html error pages
to be displayed in place of a error stack trace.

<customErrors mode="RemoteOnly" defaultRedirect="GenericErrorPage.htm">
<error statusCode="403" redirect="NoAccess.htm" />
<error statusCode="404" redirect="FileNotFound.htm" />
</customErrors>
-->
<authentication mode="Forms">
<forms name=".Authenticationmysite" loginUrl="~/Login.aspx" slidingExpiration="true" timeout="43200">
</forms>
</authentication>
<pages controlRenderingCompatibilityVersion="3.5" clientIDMode="AutoID">
<controls>
<add tagPrefix="asp" namespace="System.Web.UI.DataVisualization.Charting" assembly="System.Web.DataVisualization, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
</controls>
</pages>
<compilation debug="true">
<assemblies>
<add assembly="System.Web.DataVisualization, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
<add assembly="System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/>
<add assembly="System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A"/>
<add assembly="System.Xml, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/>
<add assembly="System.Data, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/></assemblies></compilation></system.web>
</configuration>