Today I tried to upgrade my testing site to 7.0.2. Installation is fine, I get to homepage, but then I try to login on site, and only see  'DotNetNuke Error'  and 'Object reference is not set to an instance of object' in the URL on ErrorPage.aspx form.

In a web.config, I have <customErrors mode="Off"> and <compilation debug="true">, but no stack trace is displayed. I really want to know, how to force DNN to display stack trace for this error to have a chance of resolving it.

 

The problem is, that error affected only Host user. Admin logins successfully.

I've reset all skins / container settings (SkinSrc, ContainerSrc) to NULL in dbo.TabModules and dbo.Tabs. After that under Admin user I set default tab skins and containers to new "Gravity" style - Host still cannot login.

I've enabled logging of all events:

UPDATE dbo.EventLogConfig SET LoggingIsActive = 1;

Then restarted application and looked in EventLog:

SELECT TOP(20) * FROM dbo.EventLog ORDER BY LogCreateDate DESC;

And (at last) I see a stack trace. In top of it:

System.NullReferenceException: DotNetNuke.UI.ControlPanels.ControlBar.GetHostTabs() in c:\Dotnetnuke\admin\ControlPanel\ControlBar.ascx.cs:line 924

By now I fixed host login problem just by switching back to RibbonBar:

UPDATE dbo.HostSettings SET SettingValue = 'Admin/ControlPanel/RibbonBar.ascx' WHERE SettingName = 'ControlPanel';

I assume that this error is caused by missing host tabs in old DNN version, which just has less features in host menu, or in contrary - by non-standard tabs, added manually to a host menu.