Phillips had an odd view of the Bible. Even though God may have been involved in the process, whenever you have an amalgam of divine action and human action the result is going to be imperfect in some measure in virtue of the fact that human beings make mistakes. This is a point often made by non-Christians. But after all, men wrote it and men make mistakes. Usually it's left at that, as if all one has to do is point to the fact that human beings are involved in the process and that is adequate to show that the product, therefore, is fallible.
Men make mistakes.
End of issue. The answer is actually quite simple. Just because men are capable of making mistakes doesn't mean that they in fact made mistakes when they wrote the Bible. You can't presume error is certain simply because error is possible. The conclusion simply doesn't follow from the premises.