Can you try to install the utility on a different computer? Disable anti-virus software and firewall.
How about status of all light on powerline adapters? In some cases, even if they are not detected by utility, you may be able to access internet if they are paired.

Thank you for your anwser. I just saw that the adaptator close to the modem has no light on, the one connected to the computer has the middle light missing, the pair button does not seem to work. This is new however, before that I was able to pair the adaptators. Should I still try to install the utility on an other computer? Is it possible to have permamently damaged the adaptators by installing the wrong software?

EDIT: I just tried to install the utility on another PC, and it crash on launch. I disabeld my anti virus on installation and launch. Here is the error report:
Signature du problème :
Nom d’événement de problème: APPCRASH
Nom de l’application: Utilitaire Courant Porteur.exe
Version de l’application: 2.0.2.1
Horodatage de l’application: 5317e571
Nom du module par défaut: Utilitaire Courant Porteur.exe
Version du module par défaut: 2.0.2.1
Horodateur du module par défaut: 5317e571
Code de l’exception: c0000005
Décalage de l’exception: 00008578
Version du système: 6.1.7601.2.1.0.768.3
Identificateur de paramètres régionaux: 2060
Information supplémentaire n° 1: 0a9e
Information supplémentaire n° 2: 0a9e372d3b4ad19135b953a78882e789
Information supplémentaire n° 3: 0a9e
Information supplémentaire n° 4: 0a9e372d3b4ad19135b953a78882e789

I don't have any other computer with an ADSL port to remake the installation.

I just saw that the adaptator close to the modem has no light on, the one connected to the computer has the middle light missing

All lights are off on one adapter? Did you try different power sockets? Maybe it is faulty.
As to another adapter, if there is no adapter talking to it, the middle light won't be on.
You should check the one with no lights...

I just checked and it seem to be broken, I put it on different power sockets that work but the light never went on. The adaptator never moved, is it broken? Can I replace it?

Go ahead to repalce it under warranty.