This code gives no errors, but does not update the base tables of the view "intrancust" -- Why?

SET MULTILOCKS ON

if !used('intrancust')
use intrancust
else
select ('intrancust')
endif

lSuccess=CURSORSETPROP("Buffering", 3, "intrancust")
IF lSuccess = .T.
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
=TableUpdate(1, .T., 'intrancust')

=MESSAGEBOX("Operation successful!",0,"Operation Status")
ELSE
=MESSAGEBOX("Operation NOT successful!",0,"Operation Status")
ENDIF