{ERROR: Message}
This is only valid in preupdate rules. It will prevent the update from going forward and return an alert to the user with the text Message. Note that several messages may be accumulated and returned in the alert to the user as all the rules are executed without updating the database. Contrast this with the {STOP: Message} action where execution is stopped immediately.
You may use the standard escape characters in the error message. The most common requirement is to use \n as a linefeed within your message.
