Outlook 2003 “Duplicate Contact Detected” dialog box will not pop up

Problem:
The contact duplicate detection pop up message box wont appear
to warm you that there’s a duplicate contact…etc..everytime you click the “save and close” option on the contact

Action taken:
1)tested on the user’s and my outlook 2003 and checked the “check for duplicate contacts” under the contact option.

2)tried to creat couple new contact and try to update it and still does not pop up..However,it works on my outlook 2007..

3)dragging contact file to contact list works but as soon as you open up that same file and go “save and close” button on the standard toolbar, then no duplicate detection pop up message

Please assist thanks
Xinzhi