Sorry I was not read the help carefuly,
Is it possible some users to try to write records simultaniously?
May be the cikle will prevent lose data.

m.gnError = 0 
on error m.gnError = error()

BEGIN TRANSACTION
....
DO WHILE .NOT. FLOCK() && You decide how many cikles to wait
ENDDO
INSERT .....

TableUpdate(.t., "Stafile") && Just in case :o)
if m.gnError = 0
  end transaction 
else 
   rollback 
endif

Against Stupidity the Gods themselves Contend in Vain - Johann Christoph Friedrich von Schiller
The only thing normal about database guys is their tables.