Hi Antonio

>If I try to add a new record with a repeated value in this field, the error handling routine in the "updaterows" method of the "txtbtns" container, traps the error and clears it before I get the chance of evaluating the ocurrence of the error by means of the ERROR() function in my form.

You wouldn't handle this in an error event, but catch it in the Valid event of the Primary Key's textbox.

>Although I know it is not a good practice to let the user submit values for a primary index field

Your right, is there any special reason your doing it this way? My supplied framework has a nextid table and a nextid method. The default value of the PK field is: nextid('fieldname'), then the nextid program gets the newest id for that field out of the table and adds one to it. There should be no reason the user knows the PK even exists, however I don't know your particular scenario.