Binary search tree insertion method

I'm pretty sure I've isolated my bug to my insertion method. I'm not sure whether it's issues with my logic or a pointer issue. I've done the following:

bool BinarySearchTree::treeInsert(string courseNumber, string courseTitle)
{

Course * z = new Course(courseNumber, courseTitle);
Course *x, *y;
y = NULL;
x = root;

while (x != NULL){
    y = x;

    if(z->getCourseNumber() < y->getCourseNumber()){
        x = x->getLeft();
    } else{
        x = x->getRight();
    }
}

z->setParent(y);

if (y == NULL){
    root = z;

} else {
    if(z->getCourseNumber() < y->getCourseNumber()){
        y->setLeft(z);
        z->setParent(y);
    }
    else {
        y->setRight(z);
        z->setParent(y);
    }
}
}

Is there something that stands out that I'm missing here?

Thanks in advance.