Yes, that is indeed the error that I continue to receive.  This happens at Line 227 in Reflection.vb of the DotNetNuke.Library project.  The function getting called has the following arguments:

CreateObject("MyCompany.Provider.PortalSqlDataProvider", "MyCompany.Provider.PortalSqlDataProvider", "True")

As you can see, I have removed the assembly from the type now.  But it happens regardless to if the assembly name is in there or not.

Here is the exception:

MESSAGE:
Value cannot be null. Parameter name: type

SOURCE: mscorlib

STACK TRACE:

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:\Web\v4.05.03_Source\Library\Components\Framework\Reflection.vb:line 227

System.ArgumentNullException: Value cannot be null.  Parameter name: type

[EDIT]

I should add the function in the source.  Here is the function getting called in Reflection.vb:

Public Shared Function CreateObject(ByVal TypeName As String, ByVal CacheKey As String, ByVal UseCache As Boolean) As Object

    ' dynamically create the object
    Return Activator.CreateInstance(CreateType(TypeName, CacheKey, UseCache))  'LINE 227

End Function 

[/EDIT]

Checkout your DataProvider Class, how are you creating the provider: Like this?

objProvider =

CType(Framework.Reflection.CreateObject("data", "MyCompany.Provider.PortalSqlDataProvider", ""), DataProvider)

This is the SqlDataProvider for the portal, not a module.  However, during troubleshooting, I have used such code to regenerate the error.  It does indeed return the same error on the same line of code.  The SqlDataProvider for the portal does not use a line to instantiate itself like that.  All of the other providers I have looked at so far do though.