CGAL::Precondition_exception

[BrunoSalerno]

I'm using version 0.21 hosted here . But, since you are the author, I post the issue here. I have circa 30K points and 50~ tags. All in one file. When I run clustr I get this error always after a certain tag:

terminate called after throwing an instance of 'CGAL::Precondition_exception'
  what():  CGAL ERROR: precondition violation!
Expr: ! is_infinite(e)
File: /usr/include/CGAL/Triangulation_2.h
Line: 987

if I remove just 2 points (one belonging to the last 'succesful' tag and one belonging to the following one), everything works fine. Why do I have to delete these 2 points? Is this a bug? The points look fine.