Stocknum is a primary. I'm getting a ~Uniqueness of stocknum is violated. How?
Here's the code:

SET MULTILOCKS ON
&&OPEN DATABASE (HOME(2) + 'data\testdata')
&&USE customer && Open customer table

* Set buffering mode and store logical result
lSuccess=CURSORSETPROP("Buffering", 3, "intrancust")
IF lSuccess = .T.
REPLACE stocknum WITH Thisform.Text6.VALUE
Replace chgperkt With Thisform.CHARGEPERKARAT1.VALUE
Replace measure with Thisform.MEASUREMENTS1.VALUE
REPLACE cut WITH Thisform.Combo3.VALUE
REPLACE colors WITH Thisform.Combo2.VALUE
REPLACE clarity WITH Thisform.Combo1.VALUE
REPLACE p_descript WITH Thisform.PRODUCTDESCRIPTION1.VALUE
REPLACE entered WITH Thisform.Text1.VALUE
REPLACE removed WITH Thisform.Text2.VALUE
REPLACE invoiced WITH Thisform.Text3.VALUE
REPLACE total_chg WITH Thisform.Text4.VALUE
REPLACE karatwt WITH Thisform.Text5.VALUE
REPLACE transdesc WITH Thisform.trans_descript.VALUE
REPLACE company WITH Thisform.Text7.VALUE
REPLACE track_num WITH Thisform.Text8.VALUE
=TableUpdate(0, .T., 'intrancust')
=MESSAGEBOX("Operation successful!",0,"Operation Status")
ELSE
=MESSAGEBOX("Operation NOT successful!",0,"Operation Status")
ENDIF