I Just recently installed DNN 8.0.0.0 and it is perfect.

I installed the latest stable version of DNN Blog but I faced this problem when I tried to add a new blog. 

The Manage.ascx failed to load: 

Error: is currently unavailable. DotNetNuke.Services.Exceptions.ModuleLoadException: Unknown server tag 'dnn:DNNGrid'. ---> System.Web.HttpParseException: Unknown server tag 'dnn:DNNGrid'. ---> System.Web.HttpParseException: Unknown server tag 'dnn:DNNGrid'. ---> System.Web.HttpException: Unknown server tag 'dnn:DNNGrid'. at System.Web.UI.TagPrefixTagNameToTypeMapper.System.Web.UI.ITagNameToTypeMapper.GetControlType(String tagName, IDictionary attribs) at System.Web.UI.MainTagNameToTypeMapper.GetControlType2(String tagName, IDictionary attribs, Boolean fAllowHtmlTags) at System.Web.UI.MainTagNameToTypeMapper.GetControlType(String tagName, IDictionary attribs, Boolean fAllowHtmlTags) at System.Web.UI.RootBuilder.GetChildControlType(String tagName, IDictionary attribs) at System.Web.UI.ControlBuilder.CreateChildBuilder(String filter, String tagName, IDictionary attribs, TemplateParser parser, ControlBuilder parentBuilder, String id, Int32 line, VirtualPath virtualPath, Type& childType, Boolean defaultProperty) at System.Web.UI.TemplateParser.ProcessBeginTag(Match match, String inputText) at System.Web.UI.TemplateParser.ParseStringInternal(String text, Encoding fileEncoding) --- End of inner exception stack trace --- at System.Web.UI.TemplateParser.ProcessException(Exception ex) at System.Web.UI.TemplateParser.ParseStringInternal(String text, Encoding fileEncoding) at System.Web.UI.TemplateParser.ParseString(String text, VirtualPath virtualPath, Encoding fileEncoding) --- End of inner exception stack trace --- 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 System.Web.UI.TemplateControl.LoadControl(String virtualPath) at DotNetNuke.UI.ControlUtilities.LoadControl[T](TemplateControl containerControl, String ControlSrc) at DotNetNuke.UI.Modules.WebFormsModuleControlFactory.CreateControl(TemplateControl containerControl, String controlKey, String controlSrc) at DotNetNuke.UI.Modules.WebFormsModuleControlFactory.CreateModuleControl(TemplateControl containerControl, ModuleInfo moduleConfiguration) at DotNetNuke.UI.Modules.ModuleControlFactory.LoadModuleControl(TemplateControl containerControl, ModuleInfo moduleConfiguration) at DotNetNuke.UI.Modules.ModuleHost.LoadModuleControl() --- End of inner exception stack trace ---

Thanks for mentioning this change of DNN 8. However, I'm facing this problem in BLOG version 06.02.02 which the most latest one. 

I think we need to wait them to recompile the DNN BLOG and release another version.

I downloaded the source and tried that but could recompile it.

Any suggestions !

What Chris Hammond said is the right answer, you just need to recompile the source again using the new dotnetnuke libraries.

I did that and it worked.

you have to do the following :

1- download the source of latest version of the blog from github.

2- open it using VS and remove the old reference for Dotnetnuke.dll , Dotnetnuke.Web (that actually used to have the dnn telerik wrappers controlls)

3- add the new library that contains the deprecated dnn wrappers controls for telerik which is (Dotnetnuke.Web.Deprecated.dll) of course you can get it from the DNN 8 bin folder.

4- now you need to go to Manage.ascx file and comment out the register directives for the following namespaces :

<%--<%@ Register TagPrefix="dnn" Namespace="DotNetNuke.UI.WebControls" Assembly="DotNetNuke" %>--%>

<%--<%@ Register TagPrefix="dnn" Assembly="DotNetNuke.Web" Namespace="DotNetNuke.Web.UI.WebControls" %>--%>

5- you have to register the new directive for dnn telerik controls that is in Deprecated dll you just added to reference in step 3

<%@ Register TagPrefix="dnn" Namespace="DotNetNuke.Web.UI.WebControls" Assembly="DotNetNuke.Web.Deprecated" %>

Kindly note that you have to do step 5 in any other *.ascx file that use dnn telerik controls .

6- final step rebuild the solution and you will get error because you have to update another reference for  " System.Web.Http.dll" because the DNN 8 use the new one that Blog source does have the old. so Just remove the reference and added new "System.Web.Http.dll" from the DNN 8 bin folder.

7- Build again and hopefully it works.

8- go to the obj/release folder in the solution and you will see the "DotNetNuke.Modules.Blog.dll" complied  just copy it to your DNN 8 bin folder and of course you will asked to replace the it with already old existed one.

9- replace the Manage.ascx file as well in Desktop Modules folder in your DNN8.  and any other changed *.ascx files. 

10- Enjoy , and please tell me in case anything happened ! :)