Problems with developer 2000

I am learning Developer 2000 and am working on a project now and am facing some problems. I would be very grateful if anyone cd help me out.

1. In a master-detail form: In the detail part of the form if i have multi-line items.. eg. Part_Id (Records displayed/fetched = 4) ..How do i distinguish each instance of the item 'Part_id'(out of the 4 or more instances). The reason i ask is i wd like to validate each time the user enters a part_id that he is not repeating one that he has already entered in the first or any prior line!
2. If i have Save and Query in the same form and i try to move on to query mode why do my validations(when-validate-item) for the items in the form trigger off when i have specifically said 'If :system.mode = 'NORMAL' then...' To avoid this for now i have resolved by keeping all the validations in the Save button,but is that the only solution?

3.I have created a menu and generated it. Then i have attached it to a form. But now when i run the form i get an error saying 'Cannot read the file('C: \....menu_name.mmx') and it also displays an error number.And then i get another error box saying Error creating menu!. Is there some place i can look up this error no: or any other error no: for that matter. Can u also let me know why i am getting this error cos i have generated the menu b4 attaching it to the form and the .mmb and .mmx i checked exist in the same directory to which i am referencing to!
If any of u cd address my problems and give me solutions and suggest some good books i wd really appreciate it.
Thanks,
Smita

-----------== Posted via Deja News, The Discussion Network ==---------- http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own Received on Mon Mar 29 1999 - 16:44:26 CST