The first thing to check when using the 43xx modules with Visual Basic is that you have the proper support installed from NI-DAQ.
It is not quite intuitive, but for Visual Basic support, you also need to make sure the CVI MSVC support is installed from your NI-DAQ driver. This is because the NI-435x driver uses this library.
If you have already installed NI-DAQ, select the NI-DAQ Setup from Start >> Programs >> National Instruments DAQ to install LabWindows/CVI support.