I upgraded 4.4.0 --> 4.4.1 and it went fine.

Created a child portal. No problems noted or logged. Then change the skin from the DNN default blue to the DNN grey, and it bombs out. No page appears, and this in the querystring:

tabid=101&error=Value+cannot+be+null.%0d%0aParameter+name%3a+type&content=0

In the log file:

ActiveTabName: Home
RawURL: /Default.aspx?tabid=101&error=Value+cannot+be+null.%0d%0aParameter+name%3a+type&content=0
AbsoluteURL: /Default.aspx
AbsoluteURLReferrer:
UserAgent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)
DefaultDataProvider: DotNetNuke.Data.SqlDataProvider, DotNetNuke.SqlDataProvider
ExceptionGUID: feef0931-692d-40de-b75d-19878d84a6e8
InnerException: Value cannot be null. Parameter name: type
FileName:
FileLineNumber: 0
FileColumnNumber: 0
Method: System.Activator.CreateInstance
StackTrace:
Message: DotNetNuke.Services.Exceptions.PageLoadException: Value cannot be null. Parameter name: type ---> System.ArgumentNullException: Value cannot be null. Parameter name: type at System.Activator.CreateInstance(Type type, Boolean nonPublic) at DotNetNuke.Framework.Reflection.CreateObject(String TypeName, String CacheKey, Boolean UseCache) at DotNetNuke.Framework.Reflection.CreateObject(String ObjectProviderType, String ObjectProviderName, String ObjectNamespace, String ObjectAssemblyName, Boolean UseCache) at DotNetNuke.Modules.NavigationProvider.NavigationProvider.Instance(String FriendlyName) at DotNetNuke.UI.Skins.NavObjectBase.InitializeNavControl(Control objParent, String strDefaultProvider) at DotNetNuke.UI.Skins.Controls.TreeViewMenu.OnInit(EventArgs e) at System.Web.UI.Control.InitRecursive(Control namingContainer) at System.Web.UI.Control.InitRecursive(Control namingContainer) at System.Web.UI.Control.InitRecursive(Control namingContainer) at System.Web.UI.Control.AddedControl(Control control, Int32 index) at System.Web.UI.ControlCollection.Add(Control child) at DotNetNuke.Framework.DefaultPage.Page_Init(Object sender, EventArgs e) at System.Web.UI.Control.OnInit(EventArgs e) at System.Web.UI.Page.OnInit(EventArgs e) at DotNetNuke.Framework.PageBase.OnInit(EventArgs e) at System.Web.UI.Control.InitRecursive(Control namingContainer) at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) --- End of inner exception stack trace ---

Whitespace and compression both turned off, if that has anything to do with it, though not commented out in web.config.

Are there missing DLLs in the 441 upgrade pckg? The 440 from which I upgraded was an install, not an upgrade from previous version.