>I found that using APPEND BLANK and REPLACE (in combination with buffering) is easier to control. After doing the changes, I can do a TableUpdate(), and if this fails, get error information with aerror(). I am not sure if I can get the same level of details with INSERT INTO, but perhaps it works, too.

You will get the same error information with INSERT-SQL as you do with the two commands if you're using buffering.