BEF, Views and reset buttons

Hi,

recently, I have noted that all my «reset» buttons (views: Advanced > Exposed form style: Settings > reset button) had stoped working (firefox said: problem with cookies). At the same time, I tried to reconfigure BEF without success (HTTP: 500 Ajax...); ie I could not get access to its «settings».

So I disabled BEF and Uninstall it. Reinstall it and tried to add it again to a view and I got this message:

Une erreur HTTP AJAX s'est produite.
Code de statut HTTP : 500
Informations de débogage ci-dessous.
Chemin: http://hangar217model.com/fr/admin/structure/views/ajax/display/trouver_...
StatutTexte: Internal Server Error
ReponseTexte:

It's like if an old setting was still «stuck» somewhere in the database (sort of speak).

Is it possible that some sort of conflict between BEF and Views made the «reset button» stop working? What could be the solution for making the reset button and BEF work again?

Thanks for your time.