You recieve the following error on Windows 2008:

Server Error in Application "DOMAIN.com.COM"

Internet Information Services 7.0
Error Summary
HTTP Error 500.21 - Internal Server Error
Handler "Plesk_Handler_05170778" has a bad module "ManagedPipelineHandler" in its module list
Detailed Error Information
Module    IIS Web Core
Notification    ExecuteRequestHandler
Handler    Plesk_Handler_05170778
Error Code    0x8007000d
Requested URL    http://DOMAIN.com/Default.aspx
Physical Path    C:\inetpub\vhosts\DOMAIN.COM\httpdocs\Default.aspx
Logon Method    Anonymous
Logon User    Anonymous
Most likely causes:

    * ASP.NET is not installed or incompletely installed.
    * A configuration typographical error occured.
    * Unfavourable pre-condition evaluation exists.

Things you can try:

    * If ManagedPipelineHandler is missing, ensure that:
          o ManagedEngine is in <globalModules>.
          o ManagedPipelineHandler is in <handlers>, with correct pre-conditions.
    * Install ASP.NET.
    * Ensure all system.webServer/handlers@modules are in system.webServer/modules@name.
    * Review pre-conditions in the <modules> and <handlers> sections.

Links and More Information IIS core does not recognize the module.

View more information »

Under windows 2008, the Plesk control panel may erroreously att items to the web.config file.

1)  Open up the web.config file.
2)  Scroll to the bottom of the web.config file.
3)  Replace the entire section of <System.webserver> that looks like:

-------------------------------------------

<system.webServer>
        <modules>
            <add name="ScriptModule" type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" preCondition="managedHandler" />
            <add name="Compression" type="DotNetNuke.HttpModules.Compression.CompressionModule, DotNetNuke.HttpModules" preCondition="managedHandler" />
            <add name="RequestFilter" type="DotNetNuke.HttpModules.RequestFilter.RequestFilterModule, DotNetNuke.HttpModules" preCondition="managedHandler" />
            <add name="UrlRewrite" type="DotNetNuke.HttpModules.UrlRewriteModule, DotNetNuke.HttpModules" preCondition="managedHandler" />
            <add name="Exception" type="DotNetNuke.HttpModules.Exceptions.ExceptionModule, DotNetNuke.HttpModules" preCondition="managedHandler" />
            <add name="UsersOnline" type="DotNetNuke.HttpModules.UsersOnline.UsersOnlineModule, DotNetNuke.HttpModules" preCondition="managedHandler" />
            <add name="DNNMembership" type="DotNetNuke.HttpModules.Membership.MembershipModule, DotNetNuke.HttpModules" preCondition="managedHandler" />
            <add name="Personalization" type="DotNetNuke.HttpModules.Personalization.PersonalizationModule, DotNetNuke.HttpModules" preCondition="managedHandler" />
        </modules>
        <handlers>
            <add name="AJAX_ScriptResourceHandler" path="ScriptResource.axd" verb="GET,HEAD" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" preCondition="integratedMode,runtimeVersionv2.0" />
            <add name="AJAX_AppServiceHandler" path="*_AppService.axd" verb="*" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" preCondition="integratedMode,runtimeVersionv2.0" />
            <add name="AJAX_WebServiceHandler" path="*.asmx" verb="*" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" preCondition="integratedMode,runtimeVersionv2.0" />
            <add name="LogoffHandler*" path="Logoff.aspx" verb="*" type="DotNetNuke.Services.Authentication.LogOffHandler, DotNetNuke" preCondition="integratedMode,runtimeVersionv2.0" />
            <add name="RSSJandler" path="RSS.aspx" verb="*" type="DotNetNuke.Services.Syndication.RssHandler, DotNetNuke" preCondition="integratedMode,runtimeVersionv2.0" />
            <add name="LinkClickHandler" path="LinkClick.aspx" verb="*" type="DotNetNuke.Services.FileSystem.FileServerHandler, DotNetNuke" preCondition="integratedMode,runtimeVersionv2.0" />
            <add name="CaptchaHandler" path="*.captcha.aspx" verb="*" type="DotNetNuke.UI.WebControls.CaptchaHandler, DotNetNuke" preCondition="integratedMode,runtimeVersionv2.0" />
        </handlers>
        <validation validateIntegratedModeConfiguration="false" />
    </system.webServer>
--------------------------------

With the section listed below

--------------------------------

     <system.webServer>
        <modules>
            <add name="ScriptModule" type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" preCondition="managedHandler" />
            <add name="Compression" type="DotNetNuke.HttpModules.Compression.CompressionModule, DotNetNuke.HttpModules" preCondition="managedHandler" />
            <add name="RequestFilter" type="DotNetNuke.HttpModules.RequestFilter.RequestFilterModule, DotNetNuke.HttpModules" preCondition="managedHandler" />
            <add name="UrlRewrite" type="DotNetNuke.HttpModules.UrlRewriteModule, DotNetNuke.HttpModules" preCondition="managedHandler" />
            <add name="Exception" type="DotNetNuke.HttpModules.Exceptions.ExceptionModule, DotNetNuke.HttpModules" preCondition="managedHandler" />
            <add name="UsersOnline" type="DotNetNuke.HttpModules.UsersOnline.UsersOnlineModule, DotNetNuke.HttpModules" preCondition="managedHandler" />
            <add name="DNNMembership" type="DotNetNuke.HttpModules.Membership.MembershipModule, DotNetNuke.HttpModules" preCondition="managedHandler" />
            <add name="Personalization" type="DotNetNuke.HttpModules.Personalization.PersonalizationModule, DotNetNuke.HttpModules" preCondition="managedHandler" />
        </modules>
        <handlers>
            <add name="AJAX_ScriptResourceHandler" path="ScriptResource.axd" verb="GET,HEAD" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" preCondition="integratedMode,runtimeVersionv2.0" />
            <add name="AJAX_AppServiceHandler" path="*_AppService.axd" verb="*" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" preCondition="integratedMode,runtimeVersionv2.0" />
            <add name="AJAX_WebServiceHandler" path="*.asmx" verb="*" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" preCondition="integratedMode,runtimeVersionv2.0" />
            <add name="LogoffHandler*" path="Logoff.aspx" verb="*" type="DotNetNuke.Services.Authentication.LogOffHandler, DotNetNuke" preCondition="integratedMode,runtimeVersionv2.0" />
            <add name="RSSJandler" path="RSS.aspx" verb="*" type="DotNetNuke.Services.Syndication.RssHandler, DotNetNuke" preCondition="integratedMode,runtimeVersionv2.0" />
            <add name="LinkClickHandler" path="LinkClick.aspx" verb="*" type="DotNetNuke.Services.FileSystem.FileServerHandler, DotNetNuke" preCondition="integratedMode,runtimeVersionv2.0" />
            <add name="CaptchaHandler" path="*.captcha.aspx" verb="*" type="DotNetNuke.UI.WebControls.CaptchaHandler, DotNetNuke" preCondition="integratedMode,runtimeVersionv2.0" />
        </handlers>
        <validation validateIntegratedModeConfiguration="false" />
    </system.webServer>