I have a similar problem...
basically the "help" does not see the "categories" eventhought it is right under it
There are no category modules in this page. Please add a category module to the page and assign it using module settings.
I have another dnn install that I use for testing and that one works just fine (small bug) but it works, I have tried uninstalling and reinstalling a couple of times I have tried copying from the working site, I even tried installing an older version, I get no errors during install/uninstall, when i go to the settings of the help module there is no category module in the drop down, and if I hit "update" I get an error, most likely because it is "blank":
An error has occurred.
DotNetNuke.Services.Exceptions.ModuleLoadException: Conversion from string "" to type 'Integer' is not valid. ---> System.InvalidCastException: Conversion from string "" to type 'Integer' is not valid. ---> System.formatException: Input string was not in a correct format. at Microsoft.VisualBasic.CompilerServices.Conversions.ParseDouble(String Value, NumberformatInfo Numberformat) at Microsoft.VisualBasic.CompilerServices.Conversions.ToInteger(String Value) --- End of inner exception stack trace --- at Microsoft.VisualBasic.CompilerServices.Conversions.ToInteger(String Value) at Microsoft.VisualBasic.CompilerServices.Conversions.ToInteger(Object Value) at DotNetNuke.Modules.Help.Help.get_ModuleActions() at DotNetNuke.UI.Modules.ModuleInstanceContext.LoadActions(HttpRequest Request) at DotNetNuke.UI.Modules.ModuleInstanceContext.get_Actions() at DotNetNuke.UI.Containers.ActionBase.Page_Load(Object sender, EventArgs e) --- End of inner exception stack trace ---
this renders the module completely useless and I have to delete the page to get rid of it.