Help! Samsung galaxy y error message from reboot button at cwm!

Hey Guys! So here's my problem today... You see my friend wanted a new ROM for his galaxy Y. And I, being a geek; accepted. Now when I flashed CWM, it worked fine at first but when I tried to reboot it at the CWM menu it says "Root access is missing. Root device. THIS CANNOT BE UNDONE." and there are 2 options either "-No" or "Yes - Root device (/system/xbin.".. Now, no matter what I choose it still wont boot up completely and open CWM. How do I fix this??? I don't want to ruin my friends new phone (I know it's a cheap phone, but it's "special" to my friend) !! HELP!