New Post: CKeditor on DNN 8: Custom Editor options will not load, throws error

I am on DNN 08.00.03 (5). The CKeditor version says 3.6.1 (revision 7072). I am on PowerDNN using Control Suite for upgrade package.

When I try and load 'Custom Editor Options' the window that pops up just loads the home page of the site and I get this error. Thanks for any help, Will, Maine USA.

AbsoluteURL:/Providers/HtmlEditorProviders/CKEditor/Options.aspx

DefaultDataProvider:DotNetNuke.Data.SqlDataProvider, DotNetNuke

ExceptionGUID:fa4d9bb8-951d-476a-828d-bdc4c92b0334

AssemblyVersion:8.0.3

PortalId:2

UserId:1

TabId:74

RawUrl:/Providers/HtmlEditorProviders/CKEditor/Options.aspx?mid=6575&tid=3230&minc=txtContent&porid=2&langCode=en-US

Referrer:http://mydomain.tempdomain.com/Home/Websiteadmin/Sandbox/tabid/3230/ctl/Edit/mid/6575/Default.aspx?popUp=true

UserAgent:Mozilla/5.0 (Windows NT 6.1; WOW64; rv:47.0) Gecko/20100101 Firefox/47.0

ExceptionHash:4Iv979SGl/kEjl8bt458FA==

Message:Unknown server tag 'dnn:DnnTextBox'.

StackTrace:

InnerMessage:Unknown server tag 'dnn:DnnTextBox'.

InnerStackTrace:

at System.Web.UI.TemplateParser.ParseString(String text, VirtualPath virtualPath, Encoding fileEncoding)
at System.Web.UI.TemplateParser.ParseFile(String physicalPath, VirtualPath virtualPath)
at System.Web.UI.TemplateParser.ParseInternal()
at System.Web.UI.TemplateParser.Parse()
at System.Web.Compilation.BaseTemplateBuildProvider.get_CodeCompilerType()
at System.Web.Compilation.BuildProvider.GetCompilerTypeFromBuildProvider(BuildProvider buildProvider)
at System.Web.Compilation.BuildProvidersCompiler.ProcessBuildProviders()
at System.Web.Compilation.BuildProvidersCompiler.PerformBuild()
at System.Web.Compilation.BuildManager.CompileWebFile(VirtualPath virtualPath)
at System.Web.Compilation.BuildManager.GetVPathBuildResultInternal(VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate)
at System.Web.Compilation.BuildManager.GetVPathBuildResultWithNoAssert(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate)
at System.Web.UI.TemplateControl.LoadControl(VirtualPath virtualPath)
at WatchersNET.CKEditor.Options.Page_Load(Object sender, EventArgs e)