I have been unable to generate the Primary Interop Assembly for a COM object.
The COM object has been developed with Visual Basic 6 by our company that
encapsulates common business functionality.  One method returns an ADO
connection (msado25.tlb).  At this time, it is not an option to re-write the
object with a .NET language, rather we want to use an interop assembly.

Using the Type Library Importer (Tlbimp.EXE) there is the following error
message: “TlbImp error: System.ApplicationException – Reference type library
‘ADODB’ does not have a primary interop assembly registered.”

I attempted to generate the primary interop assembly again with the
/reference:"C:\Program Files\Microsoft.NET\Primary Interop
Assemblies\adodb.dll" option with the same result.

I am able to create an interop assembly with the Tlbimp.Exe successfully
when the PIA is not generated (not using the /primary option).  An assembly
also created in the same directory named ADODB.DLL.  

The question is then, how does one generate a Primary Interop Assembly when
the source COM object uses ADO?

Thanks