Here's the error message.  What does this mean?

An error has occurred.
DotNetNuke.Services.Exceptions.ModuleLoadException: Object reference not set to an instance of an object. ---> System.NullReferenceException: Object reference not set to an instance of an object. at DotNetNuke.NavigationControl.SolpartMenuNavigationProvider.Bind(DNNNodeCollection objNodes) at DotNetNuke.UI.WebControls.SolPartActions.BindMenu(DNNNodeCollection objNodes) at DotNetNuke.UI.WebControls.SolPartActions.BindMenu() at DotNetNuke.UI.WebControls.SolPartActions.Page_PreRender(Object sender, EventArgs e) --- End of inner exception stack trace ---

My site is based on version 5.1.02;

I've had this same problem for about a month and have made little progress in solving it.  I know it affects all 5.x builds fresh from DNN including professional.  I've asked the paid support for assitance but they don't have a work around and aren't quite aware of the problem.  I "beleive" it's skin related to the SolPartActions part of the module and I did find one "Possible" related article: 

http://www.dotnetnuke.com/Community/Forums/tabid/795/forumid/92/threadid/324869/scope/posts/threadpage/1/Default.aspx

check out the reference part to: ProviderName="DNNMenuNavigationProvide

I tried this on the "Default" shipped skin with a fresh build and it had a positive affect but didn't solve the problem.  There's something deeper wrong with how the Blog View module handles Skins and CSSs but I haven't been able to find it.

check out:

http://www.dotnetnuke.com/Community/Forums/tabid/795/forumid/92/threadid/324869/scope/posts/threadpage/1/Default.aspx

I forgot to mention.  It doesn't solve the problem but it does help explain what's going on.  The problem is replicatble even from a fresh install.