I am getting the following error after trying to upgrade from 4.4.1 to 4.7.0.  Anyone have ideas?  I have tried about everything I can think of.

[ArgumentNullException: Value cannot be null.
Parameter name: type]
   System.Activator.CreateInstance(Type type, Boolean nonPublic) +2768503
   DotNetNuke.Framework.Reflection.CreateObject(String ObjectProviderType, String ObjectProviderName, String ObjectNamespace, String ObjectAssemblyName, Boolean UseCache) +582
   DotNetNuke.Data.DataProvider.CreateProvider() +47
   DotNetNuke.Data.DataProvider..cctor() +13

[TypeInitializationException: The type initializer for 'DotNetNuke.Data.DataProvider' threw an exception.]
   DotNetNuke.Common.Globals.GetUpgradeStatus() +67
   DotNetNuke.Common.Global.CheckVersion() +132
   DotNetNuke.Common.Global.Application_Start(Object Sender, EventArgs E) +477

Mitch,

This is a great question!  the exact error I ran into as well.  I have spent hours trying to resolve it to no avail.  While it didn't help me, maybe you can glean some guidance from a similar thread I opened last week: http://www.dotnetnuke.com/Community/Forums/tabid/795/forumid/107/postid/188452/scope/posts/Default.aspx

If you end up solving it, please respond to this post, because there are others out there stuggling with this.

Thanks,

Gareth

I had this same issue.

Based on my best guess regarding the cause:

This was my fourth or fifth DNN install. The others were clockwork. However, with the one that threw this error, I had installed VWD 2k8 and VB 2k8. 
When I created a new site in VWD an n Way! (Maybe the button actually just said "no", but you can appreciate the emphasis.)

This time it works like a charm. OK, not exactly, there is still the mysterious link module:

Error: Links is currently unavailable.
DotNetNuke.Services.Exceptions.ModuleLoadException: Value cannot be null. Parameter name: connectionString ---> System.ArgumentNullException: Value cannot be null. Parameter name: connectionString at Microsoft.ApplicationBlocks.Data.SqlHelper.ExecuteReader(String connectionString, String spName, Object[] parameterValues) at DotNetNuke.Modules.Links.SqlDataProvider.GetLinks(Int32 ModuleId) at DotNetNuke.Modules.Links.LinkController.GetLinks(Int32 ModuleId) at DotNetNuke.Modules.Links.Links.Page_Load(Object sender, EventArgs e) --- End of inner exception stack trace ---error  

But that statement of potential misery & aggravation is for another thread ...

Hope this helps!