"Unable to load DLL ..... Invalid access to memory location" error

I am using a third party .dll (from this website) which generates Hardware ID. I am using it as per the direction provided on that site.

    [DllImport("HardwareIDExtractorC.dll")]
    public static extern String GetIDESerialNumber(byte DriveNumber);

    private void btnGetHardwareId_Click(object sender, EventArgs e)
    {

        MessageBox.Show(GetIDESerialNumber(0));
    }

But it is raising the following error-

Unable to load DLL 'HardwareIDExtractorC.dll': Invalid access to memory location. (Exception from HRESULT: 0x800703E6)

Am i missing anything here?