Over the week-end I kept getting: "Could not connect to server"
All the time I was on the internet and was accepting friends requests and seeing the online status of friends in XMB, but I was unable to get GT5 online.
Yesterday evening there was no issue anymore to connect.
However, in the same session I had to connect again, so I suspect that upgrade 1.02 also kicks you out when you are not on community for a while.