Sorry all. There was a certain amount of nonsence in my previous posting on this topic.
The failing sql command is an fact a select into.
It fails when trying to retrieve a null value. The insert worked (I can retrieve the record
if I don't ask for the null field, so evidently the insert code is correct.
-209 is generated by ecpg.
I still don't know what "indicator" means though.
If I can reasonably be expected to understand the term, there still remains the bug that -209
is undocumented.