>>With the new dll I am now getting:
>>
>>Managed Debugging Assistant 'PInvokeStackImbalance' occurred
>> Message=Managed Debugging Assistant 'PInvokeStackImbalance' : 'A call to PInvoke function 'Siriusware.Middleware!Siriusware.Middleware.ValidationPass::Invoke1' has unbalanced the stack. This is likely because the managed PInvoke signature does not match the unmanaged target signature. Check that the calling convention and parameters of the PInvoke signature match the target unmanaged signature.'
>>
>>But no crash as before.
>
>See what the CallingConvention of the Siriuseware invoke1 is

The C++ declaration is

EXTERN_C LPCTSTR Invoke1	(LPCTSTR szIn)
{
	AFX_MANAGE_STATE(AfxGetStaticModuleState());

	pMainEngine->m_cei.Clear();
	pMainEngine->ProcessCall(CString(szIn), theApp.m_csRet);
	return theApp.m_csRet;
}

Does it help?