> That could be it. What confused me is that only the first of these
> kinds of assignments fails without warning, while the immediately
> following assignment does its job.

Yep that will be the problem. The first assignment does cause the
dataset to go into edit/insert but the value is lost. Once the
dataset is in edit/insert all is OK for the remaining assignments.

This presents the obvious work around until the problem is fixed,
explicitly place the dataset in edit/insert before doing the
assignments.

--
Geoff Worboys
Telesis Computing