crash

Server was set up in 14w34c and runned for a day smoothly. Shutted it down over night. On the next day my gf tries to login and got error message after 30 seconds
io.netty.handler.readtimeoutexception
error disappeared after deleting .minecraftfolder and fresh install of mc client.
My Client ran finely from the start on that day, but the error appeared on the next day on my client.
we updated to to d and 1.8pre1 but kept getting the error. In Fact it happens more and more.