Validator problem

I am using a validator for my form. The validator work very well and he show me the message error when the condition is true.

But when the condition is false , i can't pass to the next task. I stay all time in the same task where my validator is implemented !?

In the message validator i wrote that : if (field_passWord != field_confirmationPW) return "Error PW"; In the parameters : I let it empty.