Uniformize code for error reporting after a hook.

dev/skeletons/skeleton_page.php

htdocs/adherents/card.php

htdocs/categories/categorie.php

htdocs/comm/card.php

htdocs/comm/list.php

htdocs/comm/mailing/card.php

htdocs/comm/propal.php

htdocs/comm/propal/list.php

htdocs/comm/prospect/list.php

htdocs/commande/card.php

htdocs/commande/list.php

htdocs/compta/facture.php

htdocs/compta/facture/list.php

htdocs/compta/paiement.php

htdocs/contact/card.php

htdocs/expedition/card.php

htdocs/fichinter/card.php

htdocs/fourn/card.php

htdocs/fourn/commande/card.php

htdocs/fourn/facture/card.php