Let me explain :
This is what Dr. Meave said :
Dr Meave Leakey, one of the authors of a paper published by the leading journal Nature yesterday, said: "Their coexistence makes it unlikely that Homo erectus evolved from Homo habilis.
Notice how he uses the word "unlikely" not "impossible".
Both species must, therefore, have had their origins between two and three million years ago, a time from which few human fossils are known, and the hunt is on to find Homo erectus's real ancestor.
Here he talks about their origins and how they probably evolved in a time period about 2 - 3 million years ago. He also states that human fossils (although not many) have been found.
"But we know a bit more about the process of human evolution [as a result of this research]. It is very much like the evolutionary path of any other animal, with lots of side branches and not a single straight line that you see in cartoons."
It's like todays chimps and gorillas. Although they look similar, they evolved seperately and had little contact with each other.
The first 4-8 lines or so of the article were not written or said by any of the experts but by the author of the article, and we know how they like to dramatize their stories here and there .