Hopper8's 'Odin troubleshooting' thread stickied in General, pay particular attention to the suggestions around connectivity (I.E phone/PC not recognising each other). these still apply to you even though you're attempting to use Kies (why you'd do this & not simply flash a stock rom manually with Odin I don't know, but, anyway...).
If it's important enough to cause you grief if it's lost, back it up. No excuses
Trolling for thanks is lame
Does Samsung's auto-brightness implementation crap drive you to self-harm ? A solution !
Failure to search is the leading cause of male impotence on XDA
If you don't know how to recover if things go wrong, what are you doing flashing custom roms ?