>Mike,
>
>I've done exactly the same, but now I can not compile. It gives me an error on RAISERROR ('Can not add CartContent for the User ' + @tcUserID ,16,1)
>
>My tcUserID was passed as char(20) parameter. I've changed it to varchar(20), but it gives the same error. How can I do string concatenation in SQL Server? What could be wrong here?

It's no the way RAISERROR works.

RAISERROR ('Can not add CartContent for the User %s',16,1, @tcUserID)

See BOL for details.