Here is an example that works to me with qTranslate-X:
In /plugins/wordfenece/lib/wordfenceClass.php (line 1084)change the error message with something similar to this:
[:es]<strong>ERROR</strong>: El usuario o la contrase?a introducidos no son correctos. <a href="%2$s" title="Recuperar Contrase?a">No recuerdas tu Contrase?a</a>?[:en]<strong>ERROR</strong>: The username or password you entered is incorrect. <a href="%2$s" title="Password Lost and Found">Lost your password</a>?[:fr]<strong>ERREUR</strong>: Le nom d'utilisateur ou le mot de passe ne sont pas corrects. <a href="%2$s" title="Récupérer le mot de passe">Mot de passe oublié</a>?[:]
This example is for spanish, english and french.
Remenber to save a copy of this file in other directory to copy it again after an update.
Hope this helps someone.