Never mind, I fixed my error. I had to export my bookmarks to a .html file in Firefox, then import it into Opera using Menu > Settings > Browser > Import bookmarks and settings ... > From: Bookmarks HTML file > Import

I downloaded and installed Opera developer edition to make use of it's built in VPN and ad-blocker features. When I imported all my stuff from Mozilla Firefox (passwords, bookmarks, etc.), it wouldn't allow me to visit certain websites without opening it through Google (i.e. minecraft.net). When I uninstalled it, then re-installed it w/out importing my stuff after installation, I can visit websites just fine.

This is good as a temporary solution, but I want to have all my bookmarks and other stuff from Firefox. Is there a way to prevent this, such as importing it during installation, because I've noticed there's a setting for that.