Can't fix wordpress 3.5.1 pagination of page issue

Pre wordpress 3.5.1, I would use the following code to paginate any page, whether it be category page, an actual page page or any other.

https://pastebin.com/F8xsH8GM

Now this code has stopped working for some reason. I’ve run around the web testing solutions but none currently work.

You can see what I mean here: https://www.coreyyoungcorp.com/hunter1/news/

When you click “older posts”, the page changes and the URL suggests the pagination has worked, displaying /page/2/ but the title of the window says page not found, and as you can see by clearly looking at the page, it is displaying what is the index.php file not the page.php file with the second page of data.

Anyone know a definitive way around this?

Thanks in advance.