Ok, I see, thanks.
If I can ask for some more details, I need to understand every causes in this situation... :)
There is a rule about blessings (p24 SaS) wich says "The dice added are normally of the type associated with the skill the character is using for the check."
In this example the used skill is constitution+fortitude but the blessing add a dexterity dice nevertheless. It seems to be in contradiction with the rule to me so what don't I understand?