Well, no one can say that I didn't try. Since you clearly will not address any of the points made in the book, other than to complain about Ehrman personally, I will try and summarize for the others following this thread.
This book is broken into sections dealing with the way suffering is presented throughout the bible, and the biblical explanations for why suffering exists. These range from KK's favorite of punishment for sin through being necessary for salvation (sort of a New Testament version of "no pain, no gain"). Of all the biblical depictions of suffering, the only one that rings true to him is the one presented in Ecclesiastes, which by coincidence has always been my favorite chapter of the bible. It is pretty explicit in stating that life just isn't fair, and it isn't reasonable for any person to expect it to be. As far as the author of Ecclesiastes is concerned, faith should be a response to life's reality, not a fantasy of what we imagine life should be (in direct contrast to the article by Charlie Campbell discussed back on the first page).
After examining and commenting on the various biblical responses to suffering, Ehrman then offers his own take. In a nutshell, he believes that suffering does not exist for any higher purpose, it is just a fact of life. The most humane response, and the one that gives him the greatest comfort, is to acknowledge that we are all here for a brief time, and to take all possible steps to not just offer comfort to the afflicted, but do all one can to reduce their pain and its sources. In other words, making this the best of all possible worlds takes effort, but the result is worth it.
In the classic Jamesian-Paulian conflict, Ehrman comes down solidly on the side of works, not faith.
And no, KK, Ehrman never claims that god doesn't exist, he simply states that he can no longer have faith in your version of god.