I'm running DNN 4.8.04.

Indirect reference is being made to assembly DotNetNuke version 4.8.3.4, which contains 'DotNetNuke.Modules.Wiki.Router'. This Project references a prior version of DotNetNuke version 4.8.1.0. To use 'DotNetNuke.Modules.Wiki.Router', you must replace the reference to DotNetNuke with version 4.8.3.4 or higher. at System.Web.Compilation.AssemblyBuilder.Compile() 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) at System.Web.Compilation.BuildManager.GetVPathBuildResultWithNoAssert(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile) at System.Web.UI.TemplateControl.LoadControl(VirtualPath virtualPath) at System.Web.UI.TemplateControl.LoadControl(String virtualPath) at DotNetNuke.UI.Skins.Skin.InjectModule(Control objPane, ModuleInfo objModule, PortalSettings PortalSettings) --- End of inner exception stack trace --- at DotNetNuke.Services.Exceptions.Exceptions.ProcessModuleLoadException(String FriendlyMessage, PortalModuleBase ctrlModule, Exception exc, Boolean DisplayErrorMessage) at DotNetNuke.Services.Exceptions.Exceptions.ProcessModuleLoadException(PortalModuleBase ctrlModule, Exception exc, Boolean DisplayErrorMessage) at DotNetNuke.UI.Skins.Skin.InjectModule(Control objPane, ModuleInfo objModule, PortalSettings PortalSettings) --- End of inner exception stack trace ---

So just to be clear, are you positive your website is running 4.8.4, and not 4.8.1?

On the HOST/HOST SETTINGS page it tells you that? Or did you copy that from the "upgrade available" message?