And now when I try to compile my "Hello World" project, I get this error.
The error says that your compiler is too old and it doesn't support the C++ 2011 standard. But I'm confused: If you're doing a basic C++ Hello World program, why is Code::Blocks trying to include Qt?
I suggest you leave Qt out for now. Just focus on learning plain C++. This way, it doesn't matter if you have an old compiler.