I would never assume Humans couldn't survive in the dinosaur age. Remember, Humans survived during the end of the Big Mammals age, full of mammoths, bears, cats, etc, many times the size of today's animals, just as ferocious as dinosaurs, and a lot smarter. Humans were incredibly resourceful and cunning, more than many today give them credit for. Occupying areas with fewer carnivores, devising avoidance strategies, protective weapons, staying close to defensible positions or escape routes, camoflage... all of these tactics could be used to survive among the dinosaurs.
A (relatively) recent theory suggests that early man developed the layer of fat in his skin (similar to other aquatic mammals) by staying near the water's edge most of the time... they could catch and eat fish, and when carnivores came after them, they would run into deep water and swim to evade them.
Never underestimate the survivability of Man.