pianistimo,
you are too certain of your position. Some of these contradictions really are impossible, and more modern Christians understand why, and their faith is not threatened. Instead they are left with a greater responsibility to understand the will of God, knowing that inspiration is just as available to us as to the writers of the scriptures.
Let me give you an example. When is the last time you drank poison or were bitten by a snake? Mark says very clearly that you can do this and will suffer no harm. A number of Christian denominations use these verses in their worship practices.
Do you believe it? It is in the Bible, in black and white, with no interpretation called for.
Or, on the other hand, maybe not. We have older versions of fragments of Mark available, and these verses do not show up until about 415 AD. (I don't recall the exact date, I was very young then.)
So, you have a dilemma, I would think. If you believe the Bible is inerrant, you must drink poison, or at least believe you can without harm. If you doubt those verses, based on the evidence they were inserted later, you have to doubt the inerrancy of the whole Bible. (Unless those who did the insertion were "inspired." But the canon was supposed to be closed at some point, no reason given for why.)