Yeah I saw that, But from memory I had the same problem as well last year. Since version 7 I haven't noticed any problems, But I am only working with terrains at the moment. If I where you, I wouldn't worry to much about it. It is proberly something to do with the tutorial maybe, They where done back in 2006 ... Have a crack at the
shadow tutorials and also the ack mag tutorials (68,69) as they are more up to date.