Hi. I had the same problem with an Nvidia 9800M-GTX graphics card. Some of the textures were transparent. I could see through the sheep herder lady in the prologue as well as the fish that were hung up.
My drivers were about a year old, so I updated them to the latest level (for notebook drivers, that is), and the problem went away.
I'm not up on what the latest card models are, but if you have an Nvidia, updating the drivers might fix your problem.