Michel,
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.
Linda

>I have an operation which is executed every minute for years and once I had this:
>
>"There is already an open DataReader associated with this Command which must be closed first."
>
>This is the SQL that generated it:
>
>

>DECLARE @Numero Integer
>
>SET @Numero=1
>
>SELECT Robot.NoServer,Robot.Run FROM Robot (NOLOCK) WHERE Robot.Numero=@Numero 
>

>
>I am not sure if this could have been related to a network issue. This has happened a few months ago and I am only making a checkup on this today. When a SQL command generates this error, could it be related to such a situation?