Exporting to .dll - very strange error

For this application, we are compiling our networking component into a .dll. We are using TNL as the network framework. Has anyone successfully derived classes from TNL and compiled this successfully into a .dll?

I am getting the strangest COMPILE error when I try to subclass TNL::NetInterface, and I am dllexporting the subclass.

For example:

class __declspec(dllexport) myNetInterfaceWrapper : public TNL::NetInterface
{
public:
   myNetInterfaceWrapper(const TNL::Address &ad)
      : TNL::NetInterface(ad)
   {}
};

produces this compile error:

c:\Documents and Settings\shyam\Desktop\New Folder (2)\testApp\testApp.cpp(7) : warning C4275: non dll-interface class 'TNL::NetInterface' used as base for dll-interface class 'myNetInterfaceWrapper'
        c:\LIB_TNL\tnl\tnlNetInterface.h(143) : see declaration of 'TNL::NetInterface'
        c:\Documents and Settings\shyam\Desktop\New Folder (2)\testApp\testApp.cpp(6) : see declaration of 'myNetInterfaceWrapper'
c:\LIB_TNL\tnl\tnlNetBase.h(514) : error C2664: 'TNL::RefObjectRef::RefObjectRef(TNL::Object *)' : cannot convert parameter 1 from 'TNL::AsymmetricKey *' to 'TNL::Object *'
        Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
        c:\LIB_TNL\tnl\tnlNetBase.h(514) : while compiling class-template member function 'TNL::RefPtr<T>::RefPtr(const TNL::RefPtr<T> &)'
        with
        [
            T=TNL::AsymmetricKey
        ]
        c:\LIB_TNL\tnl\tnlNetConnection.h(101) : see reference to class template instantiation 'TNL::RefPtr<T>' being compiled
        with
        [
            T=TNL::AsymmetricKey
        ]

As soon as I remove the dllexport flag, it will compile fine. TNL::NetInterface is the only class we have noticed the error with. If I subclass TNL::Object, for example, it will export just fine.

This is very weird. Why a compile error, specifically involving the RefPtr class?? Could anyone shed some light?