* Open tables, and enable buffering
select 0
use Table1
CursorSetProp("Buffering", 5)
select 0
use Table2
CursorSetProp("Buffering", 5)
* (Repeat for other tables where you might do changes)

begin transaction

* (do some changes in Table1, and then:)
local llSuccess
llSuccess = TableUpdate()
if not llSuccess
  * Show information about the error
  local laMyError
  aerror(laMyError)
  MessageBox("Error saving Table1, error #" + trans(laMyError(1));
    + laMyError(2)) && Shows error number and error message
endif

if llSuccess
  * (do some changes in Table2, and then:)
  llSuccess = TableUpdate()
  ...
  etc.
endif

* Repeat for Table3, etc.

if llSuccess
  end transaction && This will confirm all the changes
else
  rollback && This will undo changes to all the tables
endif