The canonical way of using ad_form is to specify a form element as key.

If you add:

istruttori_id:key

to your form declaration and also a -edit_request section (even if empty) things will work.

As a side note using ad_returnredirect in this way seems unnecessarily complicated: simply add:

-action orari-inse-q \

to the form declaration and you are done.

Re Dave's comment on proper usage, I would love to learn how to use ad_form, but the documentation I have found seems light on examples, the ad_form code seemed a bit dense to read and understand on its own, and therefore a long sit-down and read-thru and pondering seemed called for, and I have never found the time to do that. Could someone be generous enough to post a good example or two showing some significant functionality in a page that obtains and processes input? That will be a fast way to learn, and I would be very, very grateful. Or if there is documentation with examples somewhere that would also be great to learn about. Thanks!!

See for a collection of articles as well under: http://openacs.org/rubick/