We recently upgraded to DNN 5.0.1 and have the Documents 4.1.0 module installed.  We're now getting the following error when a page is loaded that had a Documents module on it:

DotNetNuke.Services.Exceptions.ModuleLoadException: The type initializer for 
'DotNetNuke.Modules.Documents.DataProvider' threw an exception. ---> 
System.TypeInitializationException: The type initializer for 
'DotNetNuke.Modules.Documents.DataProvider' threw an exception. ---> 
System.ArgumentNullException: Value cannot be null. Parameter name: 
type at System.Activator.CreateInstance(Type type, Boolean nonPublic) 
at System.Activator.CreateInstance(Type type) at 
DotNetNuke.Framework.Reflection.CreateObject(String TypeName, String 
CacheKey, Boolean UseCache) in 
C:\hgwork\Trunk\DotNetNuke.Library\DotNetNuke.Library\Framework\Reflection.vb:line 
227 at DotNetNuke.Framework.Reflection.CreateObject(String ObjectProviderType, 
String ObjectProviderName, String ObjectNamespace, String ObjectAssemblyName, 
Boolean UseCache) in 
C:\hgwork\Trunk\DotNetNuke.Library\DotNetNuke.Library\Framework\Reflection.vb:line 
189 at DotNetNuke.Framework.Reflection.CreateObject(String ObjectProviderType, 
String ObjectNamespace, String ObjectAssemblyName) in 
C:\hgwork\Trunk\DotNetNuke.Library\DotNetNuke.Library\Framework\Reflection.vb:line 
94 at DotNetNuke.Modules.Documents.DataProvider.CreateProvider() at 
DotNetNuke.Modules.Documents.DataProvider..cctor() --- End of inner 
exception stack trace --- at 
DotNetNuke.Modules.Documents.DataProvider.Instance() at 
DotNetNuke.Modules.Documents.DocumentController.GetDocumentsSettings(Int32 ModuleId) 
at DotNetNuke.Modules.Documents.Document.LoadSettings() at 
DotNetNuke.Modules.Documents.Document.Page_Load(Object sender, EventArgs e) 
--- End of inner exception stack trace ---

Any ideas?