>>Two things wil disable the VFP errors, ON ERROR routine or code in an Error event. You have eliminated the Error event by running the code outside of any objects. You can check the one error setting by ?ON("ERROR").
>
>in previous attempts I've deliberately inserted an 'ON ERROR' immediately before the problem and thats had no effect either.
>
>I've just rerun it with 'ON("ERROR") in the watch window and it remains blank at the point of the problem.

Have you right clicked on the error method in the property sheet and reset it to default? Sometimes it might look like there is no code in there, but the method is still running.