VFP 6.0

I am having some trouble with:

CURSORSETPROP("Buffering",3,0)

=TableUpdate(.T.,"auth")

I am using a grid (child, "auth") and when adding a record for the gird, I immediately INSERT INTO the child (have to because all the fields in the parent form have ControlSource of auth.). All the fields are correctly InputMasked, yet I get the error message of "Function argument value, type, or count is invalid" @ the "=TableUpdate()". One possibly from the Help says "You are passing too many arguments to a function." Any suggestion what this could be?

Chuck