Hello Caindus_Dev,
I'm excited to learn that you're a developer! It's sounds like you're maybe looking to create something that works with the QuickBooks Desktop program's invoicing module. If so, that's awesome.
In these kinds of cases, I recommend reaching out to our Developer support team directly. The link you've shared is actually a part of the Developer community and it would be best to post these kinds of questions there.
In this section of the community where we are currently, I can help with tech support in terms of using the QuickBooks Desktop, but not the back-end programming side of things. That back-end side is where the error you're seeing would be originating.
If you're simply hoping to use the program for invoicing and this has nothing to do with the development side of things, there's nothing extra you need to download. You can simply open QuickBooks Desktop and select Create Invoices from the Home screen. Here's an article with more information: Create an invoice in QuickBooks Desktop
Let me know if you have more QuickBooks Desktop question. Best of luck with your development endeavours!
