Resources being double booked
 

We are using Outlook 2003 on our workstations with SBS 2003 on our server. We
took the basic appointment form in our public folders and modified it to
allow for booking of conference rooms and resources. For each room and
resource we created an account and set it up under scheduling to not allow
conflicting or duplicate scheduling. Recently however we are able to book the
same resources mulitiple times with out any errors or warnings. I have read a
couple of things about deleting the form cache and one other work around but
nothing is fixing this problem. Can anyone advise us how to prevent the the
resources from being booked more then once on the same day?? Please advise???