>3. On this screen which is not really a data entry screen, I do not set any buffering.. all I do is
>sele cma
>replace all...etc
>
>I'm wondering is this correct ?

It must be, if it works on at least your machine when running the app. Try it on another machine when you know the table is not open anywhere else - or try Erik's SCAN idea - either way, if the problem is locking, you should see more Replaces in effect if the buffering is not somehow on...you can try setting buffering explicitly off (to 1) before the Replaces, in case it is somehow on:

=cursorsetprop('buffering',1,'tablename')

- see if that helps, also.