Hi Tom, first of all this is a great script and I would like to thank you for releasing it to the public!

Can you tell me if there is a way to not allow a user to add a duplicate record (for example, check the database based on a field, eg. contact, and if it exists give an error message).

Thanks!

In the script, there is code that prevents users from registering a username that already exists in the database. You can find it in web/staff/app/cls_ps_staff.inc.php. See the CheckUsernameConflict( &$def, $id ) function. You may be able to copy and modify it for your needs.