Flores lies across Wallace's Line. Wallace's Line travels across a strait that was to deep to create a land bridge during eras of low sea level. It is therefore assumed that Homo sapiens could only arrive after the advent of sea faring. Evolutionists try to side step this evidence seeing as how it is venturing into dangerous territory to push the evolutionary time frame that far back. The evidence can not be ignored though.
Evolutionist are understandably reluctant to do either.
In fact, the whole Homo erectus thing is beginning to become a real thorn in the side of evolutionists. It seems that the dates are constantly being pushed further and further back into seemingly and often admittedly impossible regions. It was estimated that Homo erectus did not enter Europe until 500,000 years ago. Now discoveries are making a mockery of this perception. Near Ceprano, Italy, pieces of skull were found and dated to be 800 to 900,000 years old at Gran Dolina.