The problem appears to be that the name of the permission specified when the Formulaire system checks for viewing rights is hard coded, and is using the French name for the permission. The quick fix is to change it to the language you are using. For me, that's English. You'll need to make changes to these four files in the formulaire directory:

formulaire.php
index.php
blocks/formulaire_menu.php
blocks/qcm_menu.php

Look for lines that call the checkRight() method like this:

if ( $gperm_handler -> checkRight( 'Droits des categories', ...

Change the Frech permission name to your language, like this for English:

if ( $gperm_handler -> checkRight( 'Permissions of the categories', ...

The long term solution will be to use the language constants instead of hard coding the permission names. The developer has a constant for this, called _AM_CATPERM, but it appears that these files don't currently include the library files. Oh well. Hope this solves the problem for you.