Are you saying that the back doors won't open at all, or won't open from the outside, or won't open from the inside? If they won't open from the inside, make sure the child proof lever is in the proper position. Another common problem when they won't open from the inside is that the inside handle/lever goes bad. It's an easy fix... pop the door panel and 2 or 3 screws and the handle is in your handle. You can get replacements from the dealer or ebay.

Mike