>I think Bonnie is probably right. I got an error like that the other day and the problem (if I remember correctly) turned out to be an error in the SQL Stored Procedure for updating the table. As Bonnie suggests, it was hard to find because I didn't have any of my own code referencing a DataReader so I couldn't easily figure out where to look.

Yes, and in my case, I do not even have one single stored procedure. So, something triggered a data reader access at the SQL Server level.