My Server Problem

Everyone who tries to join my server keeps getting the "End Of Stream" screen i am watching the console and a bunch of people are trying to join i didnt have this problem when the server wasnt bukkit but now there are only about 3 people on at a time cause of the End of Stream thing, usually there is about 7 people on at a time? could someone PLEASE help me with this im really sad no one can join my server is there a solution to this? if so PLEASE comment and help me out D: thank you~