Thank you for your comment, Rabih.
Okay, with the driving example, instead let's say that the breaks fail. That is definitely a problem.
Dictionary.com defines a problem as: "A problem is a situation, question, or thing that causes difficulty, stress, or doubt...Real-life examples: A clogged toilet is an annoying problem. A rock in your shoe is often just a small problem. An international war is a big problem that causes many other problems for a large number of people."
These are examples of the common definition of problem. And some people will take Tolle's words to mean that if you stop thinking about these problems then they will go away.
It's true that a negative mental attitude can make a real-life problem seem worse than it is. But the opposite is also true. Being unrealistically optimistic in the face of a severe problem could hamper the ability to take real action to fix the problem.