Pagination Links 404'd on Main Index with Custom Query

I am a newbie and I am trying to add pagination of my posts to the main index with custom queries and in the custom bones theme. However, while the correct number of pages show in the pagination links, when clicking on a pagination link (i.e. 2, 3, etc. or Next >>), it gets 404’d to “Page Not Found.” Here is my code of my Main Index.php:

http://pastebin.com/nV6d07Uz

Any suggestions would be much appreciated. I think I’m complicating things with the “Upcoming” and “Past” buttons. Unfortunately, this is on a development site and I cannot supply a URL. However, an example of the URL for pagination is:

http://www.site.com/events/page/2/?sortby=upcoming

Thanks in advance for any help!