Hi, I had the same problem I only have my fone about a month and it connected to the wifi a couple of times. then stopped. I tried some of the fixes listed above but notn worked.
I no this is a bit obvious but I disconnected from my wifi and switched it off and on again and then reconnected. then i restarted kies and there was a new address shown. ie the 102 had changed to 103 so i entered that in the browser and it worked for me.
hope it helps.