Yes, I see what you mean. However, if it's possible for the word "problem" to be interpreted in two different ways, Tolle's words could be misunderstood. If he tells people that it's IMPOSSIBLE to have problems if they are fully in the Now, they might misunderstand that to mean that if they are fully in the present moment they might not actually have any real problems. I know a lot of people won't interpret it that way, but some people might. This is the problem with absolute statements that contain words like "impossible". It highlights the responsibility someone has if they are in a position of mass influence.

It would be more accurate for him to say "If you are fully in the present moment, your mind won't dwell on your problems, so you'll feel better". That I would 100% agree with.

But there is another issue within all of this: whether somebody actually has control over how much they are in the present moment, and whether they control their thoughts. But that's perhaps a whole discussion in itself.