Nadya,

Process the array laDe to remove the non-buffered alias' first (instead of checking the buffering mode inside the transaction. Then you code would be something like this;

* lsDe() already exists
LOCAL llRollBack
llRollBack = .F.
BEGIN TRANSACTION
FOR x = 1 TO ALEN(laDe,1)
   IF NOT TableUpdate(1,.F.,laDe(x,#))
      llRollBack = .T.
      EXIT
   ENDIF
ENDFOR
IF llRollBack
   ROLLBACK
ELSE
   END TRANSACTION
ENDIF