Implementing Smoothed Isotonic Regression

In the paper here the authors suggest a new way of calibrating classifiers, called Smoothed Isotonic Regression (Algorithm 1).

As I follow the algorithm along, I noticed a problem in lines 19-20: After IBL is first created, when getting to line 19 it becomes an empty list [I assume IL means IBL], which makes line 20 throw an exception.

My questions on this:

1. Is there really a problem in the algorithm or am I missing something?
2. If there really is a problem, is it straightforward to fix it? how?

Thanks.