In a section headed, "Problems with the Bible,"  Ehrman's premiere case is the matter of when Jesus cleansed the Temple -- did he do it at the start, as John says, or at the end, as Mark and the other Gospels say? I will begin by presenting my own answer to this issue, in order that we may see just how inadequately Ehrman has represented the matter:
This event presents something of an oddity, as one may find scholars who actually think John represents a more accurate tradition, while the Synoptics have mistakenly put the cleansing at the end of of Jesus' ministry. A standard answer (which has nothing to do with "piety" but with common sense historical detective work) is that Jesus cleansed the Temple twice, once at the beginning of his ministry, and once at the end. Another idea is that there was no personal witness to these events, but that they were handed down through an intermediate source and later arranged according to community needs. Of course one is constrained to ask why speculative and unknown "communities" with speculated and otherwise unknown "needs" is any better an explanation than that each evangelist chose to report a different cleansing to meet certain "needs". In both cases a theory dictates the facts rather than the other way around. The latter idea, however, has a certain advantage, aside from the simple fact that it doesn't mangle the data. Jesus as an observant Jew certainly visited the Jerusalem Temple many times in his life. Cleansing the Temple as an act of "prophetic demonstration" (as most agree it is) is not something that was likely to have been done once. Indeed, it is arguably something Jesus would have done, to some extent, on numerous visits to Jerusalem, during any one of the major Jewish festivals. One may ask the question of whether a pious Jesus would be any less incensed at the Temple abuses at any given time than another. Notably John's Gospel has a chronological marker that is quite incidental and therefore rings of authenticity: the note that the Temple has been under construction for 46 years (2:20), which places this incident in 27-28, at the beginning of Jesus' ministry (Witherington, John commentary, 87). Note as well that in John, Jesus merely orders the sellers of doves (whose wares are more likely to be able to escape) to leave, whereas in Mark and Matthew he overturns their seats, indicating a progression in reaction that suits a later cleansing.
It does remain possible that either John or the others have purposely dischronologized a single event in Jesus' ministry. But there remains no logical or historical barrier to a "dual cleansing action".
Ehrman does acknowledge a simpler form of this answer -- namely, that Jesus cleansed the temple twice in his career. I would say in line with the above that it was done at least 5 times in his career, if not more. How does Ehrman respond to this thesis? His attempts at rebuttal are sorrowful, to say the least:
The underlying assumption, of course, is that Mark and John would be obliged to report more than one such action by Jesus. If Ehrman wishes to argue this, then he must explain why such an obligation exists. It does not. We have quoted elsewhere Byrskog's Story as History concerning the selectivity of ancient historians in their reports [256f]. The rhetoriticians as writers "knew that certain matters had better not be included. Further: "As a matter of course, a selection always took place on different levels of research and writing, such as when the historian chose what particular subject to investigate or when circumstances forced him to leave out matters concerning which he could not receive sufficient information." Each writer had also to consider their audience and decide what was "worth mentioning." Needless to say, we, not being the intended audience, are in no position to make such a decision, and nor is Ehrman. A good secular example should silence critics like Ehrman who might claim that some event was "too important" to leave out :
As we see perhaps most evidently in the case of Xenophon, the essential criterion of this kind of selectivity remained quite subjective....the Hellenica Oxyrhychia, according to the London papyrus P. Oxy. 842 III 11-43, gives great prominence to the naval war of 396 BCE, while Xenophon mentions only the stir caused at Sparta in the winter of 397-396, ignoring entirely the war itself. An event that was extremely important for the Oxyrhynchus historian was not at all important for Xenophon.
One can easily imagine Ehrman arguing that the naval battle must not have happened if Xenophon said nothing about it! A key issue Byrskog notes is that the historian was supposed to interpret and report history so as to make it a bridge between the past and the present . Material was selected for relevance to the readership. John thought the latter cleansing was most relevant. Mark thought the former one was. The true test is not what Ehrman thinks ought to be included, but historical plausibility.
If Jesus made a disruption in the temple at the beginning of his ministry, why wasn't he arrested by the authorities then?
That is all that Ehrman has to offer! There are many problems indeed with this far too simple objection:
Since Ehrman as a NT scholar ought to know these things, we may ask a valid question: Why is he misreprenting the text and misrepresenting history here?