What does this mean out of range... isn't 1 in range?

Are you absolutely positively without a doubt sure that buffering is optimistic table buffering for the grid's RecordSource?

The only time I have ever had this happen to me was when I inadvertantly had optimistic row buffering set for the grid's RecordSource, only for me the error occured on READ EVENTS!

As you can well imagine, it was a real picnic to debug.