Some days ago an error occured on my DNN 7 development website (main portal) and did not go away. The portal was set up with DNN 7.0.0, and has been updated to 7.4.2 in several steps (or, let's say, whenever a new DNN 7 version was released). It was running fine, but suddenly this error appeared (there was only a a text saying "DNN Error" and "An unhandeld error has occured", and a button labeled "Return to Site"). I had a sub-portal on this installation which was working fine, but the main portal did not start. As I could not find the reason for this error I decided to delete the installation and set it up from scratch.
I also deleted the database and created a new one, I assigned the permissions and the installation went thru smoothly. I started the web site, everything looked fine. But when I tried to add a new page, I got the following error:
Error: is currently unavailable. DotNetNuke.Services.Exceptions.ModuleLoadException: Could not load type 'Dnn.Modules.Tabs.ManageTabs'. ---> System.Web.HttpParseException: Could not load type 'Dnn.Modules.Tabs.ManageTabs'. ---> (etc.)
Whatever I do fires an exception like that, e.g when I go to Admin :: Languages, I get this one:
Error: Language Management is currently unavailable. DotNetNuke.Services.Exceptions.ModuleLoadException: Could not load type 'Dnn.Modules.Languages.LanguageEnabler'. ---> (etc.)
Or Host :: Dashboard:
Error: Dashboard is currently unavailable. DotNetNuke.Services.Exceptions.ModuleLoadException: Could not load type 'Dnn.Modules.Dashboard.Dashboard'. ---> System.Web.HttpParseException: Could not load type 'Dnn.Modules.Dashboard.Dashboard'. ---> (etc.)
When I close the browser and re-open it, I get an empty page (which is correct, as I installed the empty template) with two red error boxes saying (both): "An error has occured. An error has occured." Whatever I do (there is not too much, but e.g. clicking the login link, I get the same errors.
I have another DNN 7.4.2 portal on this machine which runs fine. I checked the permissions, I deleted the cache, I deleted the browser cache and cookies, I stopped the app pool and deleted the "ASP.Net Temporary Files" folder (under C:\Windows\Microsoft.NET\Framework\v4.0.30319 and C:\Windows\Microsoft.NET\Framework64\v4.0.30319) and restarted the app pool - nothing did help. I compared all the settings in IIS manager and web.config - all the same so far, except some stuff on the other portal that is needed for AD Login, another menu or stuff like this. And: in the [system.webServer] section I found the sections [modules] and [handlers] - on the other installation these were called [httpModules] and [httpHandlers], but when I changed these, I got an internal server error.
I started all over again. Same thing. I started again with DNN 7.4.1 - same thing.
Anyone out there who has an idea what could be wrong?
Happy DNNing! Michael