Oi, MariaE, I can relate! I pretty much always have an audio book going in my car so those kinds of things grate my nerves as well. Mispronunciations and putting the emPHASis on the wrong sylLABle is unforgivable. I mean, I can forgive the reader for not knowing everything but is no one else listening? The producer, the people in the sound booth, whatever?
I was actually going to post that I've quit audio book specifically if the reader's voice bothers me. I normally love audio books "read by the author. So I checked out a book by Amy Tan (whose books that I have read are very good) that was read by the author.
Oh boy. Her voice was sort of high pitched squeaky and I couldn't make it past about half way through the first disc. The reader can really make or break an audio book for me.