I think I've figured out what was wrong.
In the reload tab in QMC, I entered some script parameters : Language in Parameter names and US;F in Parameter value. The document is generated both in english or in french and users have access to one of them according to what I had entered in my security tab.
The problem came from the fact that I had reinitialized the security tab and so for the application, there was no one who was supposed to access to the english version.
Because of the way I scripted the application, the English version couldn't be generated.