There have been a couple of misguided answers to this one- for the record, as a race, Zabrak have incredible willpower and general mental control. The reason Kreia couldn't read him is simply because Bao-Dur didn't want her to.
You, on the other hand, are another story. If you listen, he's actually actively trying to use that link to get private messages through to you.
From the cut sound files:
Bao-Dur: I know you can hear me. I've always known. It is why I followed you. I have destroyed planets for you, general. But now, just once, if we could save... something in this galaxy. I need to do this or I will die inside, like I died on Malachor V. You know where you must go. It calls to you still. And she must be stopped, there, now- or she will bring the screams of Malachor V to the galaxy, just as we carried the echo all this way. Now Malachor V comes to us- and I wish to face it this last... time..."
Have I mentioned I love this guy?