counter example not working

I am trying out [temporal actions example](https://github.com/AI-Planning/modeling-in-pddl/blob/main/exercises/schlumberger/3_hello_deaf_world/temporal_solution). I am using popf installed with planutils.

The following are the error I am getting. Would you please describe how you set up the planner?
```
/home/fred/.planutils/bin/popf /tmp/domain--296499-cG32eWZhL1LS-.pddl /tmp/problem--296499-tyrdfYu6vs0r-.pddl
Number of literals: 1
Constructing lookup tables:
Post filtering unreachable actions:
Recognised a monotonic-change-induced limit on -1.000*var0(counter)
- Must be >= -3.000
Pruning (hello-world) - never appeared in initial RPG
Initial heuristic = -1.000
;; Problem unsolvable!
; Time 0.12
Planner found 1 plan(s) in 0.549secs.
```
planner output is just a blank.