Ok I cant get into chapter four what quest do you have to do to get into it? If you know were is this quest?

Have you cleared out the bandit camp to the north-east of Beregost? If so, you move onto the Cloakwood Mine which is in the section of headland south of the river of Baldur's Gate itself. Or put another way, north of Candlekeep.

Let us know what you've done so far, and we'll see where you need to go/what to do next.

ok I need to clear the bandit camp

Ah sweet youth....it wasn't too long ago that I was asking questions like this and Lord Brass was answering them for me...AHHH the good ole days