Unable to open device

[CommanderLake]

I have a 2208B and when I invoke this function it returns 0, the device works just fine in the Picoscope software.
[DllImport(_DRIVER_FILENAME, EntryPoint = "ps2000_open_unit")]
public static extern short OpenUnit();

[Martyn]

You will need the ps2000a drivers and examples, not the ps2000 ones which are for the older models in the series.