Error while installing Forticlient on windows 7

When I'm trying to install forticlient v5.4 on my computer (windows 7 sp1), I have the error message "impossible de joindre les serveurs d'image" which can be translated by "unable to access image servers".

I have disable the firewall and the antivirus sofware. Windows is up to date and patch 3033929 is installed.

Any sujestion to solve this issue ?