Openfire 3.8.2 error after installing

how to understand a mistake? openfire is on Windows 2008 R2 / x86, RAM 8g. number of clients 200-250. openfired.vmoptions created a file with parameters Xms, Xmx. Working half a day and stops.

ARNING: Rate class 1 is no longer rate-limited, according to server

22.08.2013 9:13:14 net.kano.joscar.ratelim.RateClassMonitorImpl updateRateInfo

WARNING: Rate class 1 is no longer rate-limited, according to server

OutOfMemoryError: No more direct buffers available; trying heap buffer instead