Openfire stop working


Since this morning, my openfire stop working. Everything was ok since i start it one week ago, and it seems to stop during the night. I haven’t anything in logs files (0 octets for each log file of openfire) except warn.log :

2008.09.19 14:20:53 EXCEPTION
java.lang.OutOfMemoryError: Java heap space
2008.09.19 16:43:44 No ACK was received when sending stanza to: org.jivesoftware.openfire.nio.NIOConnection@10cb2c0 MINA Session: (SOCKET, R: /, L: /, S:

I restart the server and the problem persist. When i restart the service nothing start, it’s staying down. I haven’t any error message when un try to start it.

Someone have an idea to fix it or to have some messages which could help me to find a solution ?

best regards