Using Access Forms for Oracle

I’m using Access 2003 forms with several subforms to enter data into Oracle 11g. In my forms I have combo boxes, I select the equipment to add a record. The first record enters into the Oracle tables fine. However, when entering a subsequent record for the same equipment, the data in the main form is correct, but in the subforms a record is added but it’s a duplicate of the first record. This occurs in the subforms. Please help.