Retrieving the COM class factory for component 80040154 Class not registered - DLL is definitely in registry and app is using x86

I'm trying to integrate a Brother QL-700 label printer into a C# application that I'm writing. I've created a console application to test the printer with and added the following code (taken from the SDK on the Brother website):

class Program
{
    private const string TEMPLATE_DIRECTORY = @"c:\program files\brother bpac3 sdk\templates\";
    private const string TEMPLATE_FRAME = @"NamePlate2.LBX";

    static void Main(string[] args)
    {
        string templatePath = TEMPLATE_DIRECTORY;
        templatePath += TEMPLATE_FRAME;

        IDocument doc = new bpac.Document();

        if (doc.Open(templatePath) != false)
        {
            doc.GetObject("objCompany").Text = "Company";
            doc.GetObject("objName").Text = "Your name here...";

            doc.StartPrint("", PrintOptionConstants.bpoDefault);
            doc.PrintOut(1, PrintOptionConstants.bpoDefault);
            doc.EndPrint();
            doc.Close();
        }
        else
        {
            Console.WriteLine("Open() error: " + doc.ErrorCode);
            Console.ReadLine();
        }



    }
}

The application stops on the line where I create a new instance of bpac.Document and it throws the following error message:

System.Runtime.InteropServices.COMException: 'Retrieving the COM class factory for component with CLSID {B940C105-7F01-46FE-BF41-E040B9BDA83D} failed due to the following error: 80040154 Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG)).'

There are several other posts on Stack Overflow about this issue and I have tried some of the commonly suggested fixes:

1. The DLL in question is definitely in the Windows registry
2. I have changed the application architecture on the console application to x86

I'm still unable to make any progress. Does anyone else have any other ideas?