Error when delete record in WebDB FOrm

Hi Experts,
I create a simple webdb form with all those query,insert,update,delete options. When i query the form, all records can be retrieved, and when i tried to delete one of the record , i got following error :

Error Message
--------- --------------------------------------------
WWV-14607 Unknown Error While Building Delete Statement

Where
----------------------------
WWV_SYS_DML.PROCESS_DELETE



Please advice on this
Thanks
Lygine