> SOLVED <

I'll try to be specific for anyone else who encounters this issue. Here are a few of the starting factors involved:
[list][*] Started with a DNN 7.4 instance, upgraded to DNN 8.0.2 & performed base security updates
[*] Installed Hotcakes 3.0.1 module solution install package "Hotcakes_03.00.01_Core_Install.zip"
[*] All Hotcakes admin screens loaded correctly (/DesktopModules/Hotcakes/)
[*] Performed setup of store information, running through Setup Wizard
[*] Front-end public visible modules (such as /Store/Categories page and Category Viewer modules, /Store/Products detail page and HC Product Viewer module) displayed errors referring to "Could not load file or assembly 'System.Web.WebPages.Razor, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies"
[/list]

I confirmed that the web.config for the site had the proper references for Razor which pointed to the new 3.0.0.0 version of the various System.Web.XYZ related items:

[code=markup]








[/code]

I tried a few different ways to list, register, enforce the 3.x version of "System.Web.WebPages.Razor" however they had no effect. I also tried a few other things such as loading an older 2.0.0.0 version in the bin folder, but that didn't help either (didn't think that it would, but it really caused other problems!).

In the end, by comparing the Hotcakes stand-alone full system CMS version's web.config to this DNN instance's web.config, I found a difference for a missing System.Web.Mvc assembly that was present in the hotcakes cms version:

[code=markup]




[/code]

Once this was added to the DNN instance's web.config, everything loaded correctly in the site and for all of the Hotcakes modules.

I still got the error "An error has occurred. Error: Hotcakes Category Viewer is currently unavailable" even after adding the reference.







Please guide. Thanks in advance!

[quote=Prathyusha;594]I still got the error "An error has occurred. Error: Hotcakes Category Viewer is currently unavailable" even after adding the reference.







Please guide. Thanks in advance! [/quote]

hmmm, changing anything in the web.config would restart the site/application pool, but that's my first question... Did you restart DNN after that change?

Can you post the rest of the error message so that we can compare to make sure it's the same as the one we'd seen?

Thank you so much for your response. Yes, even after restarting the DNN application pool the problem pertains.

Here's the detailed error i received:
Error: Hotcakes Category Viewer is currently unavailable. DotNetNuke.Services.Exceptions.ModuleLoadException: Error executing child request for handler 'System.Web.Mvc.HttpHandlerUtil+ServerExecuteHttpHandlerAsyncWrapper'. ---> System.Web.HttpException: Error executing child request for handler 'System.Web.Mvc.HttpHandlerUtil+ServerExecuteHttpHandlerAsyncWrapper'. ---> System.Web.HttpCompileException: c:\inetpub\vhosts\dev.rgrta.com\httpdocs\Portals\0\HotcakesViews\RGRTA\Views\Category\_Header.cshtml(14): error CS0117: 'Hotcakes.Commerce.WebAppSettings' does not contain a definition for 'IsSocial' 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, 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.Compilation.BuildManager.GetVirtualPathObjectFactory(VirtualPath virtualPath, HttpContext context, Boolean allowCrossApp, Boolean throwIfNotFound) at System.Web.Compilation.BuildManager.GetCompiledType(VirtualPath virtualPath) at System.Web.Compilation.BuildManager.GetCompiledType(String virtualPath) at System.Web.Mvc.BuildManagerWrapper.System.Web.Mvc.IBuildManager.GetCompiledType(String virtualPath) at System.Web.Mvc.BuildManagerCompiledView.Render(ViewContext viewContext, TextWriter writer) at System.Web.Mvc.HtmlHelper.RenderPartialInternal(String partialViewName, ViewDataDictionary viewData, Object model, TextWriter writer, ViewEngineCollection viewEngineCollection) at System.Web.Mvc.Html.PartialExtensions.Partial(HtmlHelper htmlHelper, String partialViewName, Object model, ViewDataDictionary viewData) at System.Web.Mvc.Html.PartialExtensions.Partial(HtmlHelper htmlHelper, String partialViewName, Object model) at ASP._Page_Portals_0_HotcakesViews_RGRTA_Views_Category_Index_cshtml.Execute() in c:\inetpub\vhosts\dev.rgrta.com\httpdocs\Portals\0\HotcakesViews\RGRTA\Views\Category\Index.cshtml:line 9 at System.Web.WebPages.WebPageBase.ExecutePageHierarchy() at System.Web.Mvc.WebViewPage.ExecutePageHierarchy() at System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage) at System.Web.Mvc.RazorView.RenderView(ViewContext viewContext, TextWriter writer, Object instance) at System.Web.Mvc.BuildManagerCompiledView.Render(ViewContext viewContext, TextWriter writer) at System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context) at System.Web.Mvc.ControllerActionInvoker.InvokeActionResult(ControllerContext controllerContext, ActionResult actionResult) at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 filters, ActionResult actionResult) at System.Web.Mvc.Async.AsyncControllerActionInvoker.c__DisplayClass21.c__DisplayClass2b.b__1c() at System.Web.Mvc.Async.AsyncControllerActionInvoker.c__DisplayClass21.b__1e(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.End() at System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) at System.Web.Mvc.Controller.b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.End() at System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) at System.Web.Mvc.Controller.b__15(IAsyncResult asyncResult, Controller controller) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.End() at System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) at System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult) at System.Web.Mvc.MvcHandler.b__5(IAsyncResult asyncResult, ProcessRequestState innerState) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.End() at System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) at System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) at System.Web.Mvc.HttpHandlerUtil.ServerExecuteHttpHandlerAsyncWrapper.c__DisplayClassa.b__9() at System.Web.Mvc.HttpHandlerUtil.ServerExecuteHttpHandlerWrapper.c__DisplayClass4.b__3() at System.Web.Mvc.HttpHandlerUtil.ServerExecuteHttpHandlerWrapper.Wrap[TResult](Func`1 func) at System.Web.Mvc.HttpHandlerUtil.ServerExecuteHttpHandlerWrapper.Wrap(Action action) at System.Web.Mvc.HttpHandlerUtil.ServerExecuteHttpHandlerAsyncWrapper.EndProcessRequest(IAsyncResult result) at System.Web.HttpServerUtility.ExecuteInternal(IHttpHandler handler, TextWriter writer, Boolean preserveForm, Boolean setPreviousPage, VirtualPath path, VirtualPath filePath, String physPath, Exception error, String queryStringOverride) --- End of inner exception stack trace --- at System.Web.HttpServerUtility.ExecuteInternal(IHttpHandler handler, TextWriter writer, Boolean preserveForm, Boolean setPreviousPage, VirtualPath path, VirtualPath filePath, String physPath, Exception error, String queryStringOverride) at System.Web.HttpServerUtility.Execute(IHttpHandler handler, TextWriter writer, Boolean preserveForm, Boolean setPreviousPage) at System.Web.HttpServerUtility.Execute(IHttpHandler handler, TextWriter writer, Boolean preserveForm) at System.Web.HttpServerUtilityWrapper.Execute(IHttpHandler handler, TextWriter writer, Boolean preserveForm) at System.Web.Mvc.Html.ChildActionExtensions.ActionHelper(HtmlHelper htmlHelper, String actionName, String controllerName, RouteValueDictionary routeValues, TextWriter textWriter) at System.Web.Mvc.Html.ChildActionExtensions.Action(HtmlHelper htmlHelper, String actionName, String controllerName, RouteValueDictionary routeValues) at Hotcakes.Commerce.Dnn.Mvc.MvcRenderingEngine.Render(String controllerName, String actionName, String viewName, Object routeValues) at Hotcakes.Modules.CategoryViewer.CategoryViewerView.RenderView() at Hotcakes.Commerce.Dnn.Web.HotcakesModuleBase.OnLoad(EventArgs e) --- End of inner exception stack trace ---