Now I got this in the browser:
Fel: Events är för närvarande inte tillgänglig.
DotNetNuke.Services.Exceptions.ModuleLoadException: Failed to load viewstate. The control tree into which viewstate is being loaded must match the control tree that was used to save viewstate during the previous request. For example, when adding controls dynamically, the controls added during a post-back must match the type and position of the controls added during the initial request. ---> System.Web.HttpException: Failed to load viewstate. The control tree into which viewstate is being loaded must match the control tree that was used to save viewstate during the previous request. For example, when adding controls dynamically, the controls added during a post-back must match the type and position of the controls added during the initial request. at System.Web.UI.Control.LoadViewStateRecursive(Object savedState) at System.Web.UI.Control.LoadChildViewStateByIndex(ArrayList childState) at System.Web.UI.Control.LoadViewStateRecursive(Object savedState) at System.Web.UI.Control.AddedControl(Control control, Int32 index) at System.Web.UI.ControlCollection.Add(Control child) at DotNetNuke.Modules.Events.Events.LoadModuleControl() --- End of inner exception stack trace ---

Created a page named Test under the Start page. Same result...

BTW: it is a 5.6.3 installation of DNN.