This is perhaps the “big kahuna” in the whole enterprise of Evolutionary Creation, bigger even than questions related to Adam & Eve. As Jim just said, fully satisfactory answers aren’t easy to come by–but that goes also for questions about theodicy generally, not just those related to evolution.
I wrote a couple of columns that sketch one possible route, for proponents of the EC view. Specifically, you might look at parts 3 & 4 on “Theistic Evolution” here: http://biologos.org/blogs/ted-davis-reading-the-book-of-nature/series/science-and-the-bible. The Catholic theologian John Haught formulates the challenge about forcefully as it can be stated (note that he is putting it as an unbeliever might put it, for the sake of argument); see part 3 for that.
As for Ken Miller’s view of evolution and purpose–a view widely cited by opponents of the EC view (for reasons that are not hard to understand), let me suggest an alternative, from another Catholic scientist, physicist Steven Barr. Actually, Barr’s article for First Things is my personal favorite on this specific topic; I wish he’d written it for us at BL. Here it is: Chance, by Design by Stephen M. Barr | Articles | First Things. Note especially the final few paragraphs.
I hope this helps, at least somewhat.