Continuous error on openfire

did someone know about this error?, is permanent in openfire log every few time

Exception in thread “pool-10-thread-4” java.lang.AbstractMethodError

at org.jivesoftware.openfire.event.SessionEventDispatcher.dispatchEvent(SessionEve ntDispatcher.java:90)

at org.jivesoftware.openfire.handler.IQBindHandler.handleIQ(IQBindHandler.java:161 )

at org.jivesoftware.openfire.handler.IQHandler.process(IQHandler.java:65)

at org.jivesoftware.openfire.IQRouter.handle(IQRouter.java:372)

at org.jivesoftware.openfire.IQRouter.route(IQRouter.java:121)

at org.jivesoftware.openfire.spi.PacketRouterImpl.route(PacketRouterImpl.java:76)

at org.jivesoftware.openfire.SessionPacketRouter.route(SessionPacketRouter.java:10 8)

at org.jivesoftware.openfire.SessionPacketRouter.route(SessionPacketRouter.java:69 )

at org.jivesoftware.openfire.http.HttpSession.sendPendingPackets(HttpSession.java: 636)

at org.jivesoftware.openfire.http.HttpSessionManager$HttpPacketSender.run(HttpSess ionManager.java:390)

at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)

at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)

at java.lang.Thread.run(Unknown Source)

Exception in thread “pool-10-thread-8” java.util.NoSuchElementException

at java.util.StringTokenizer.nextToken(Unknown Source)

at org.jivesoftware.openfire.sasl.SaslServerPlainImpl.evaluateResponse(SaslServerP lainImpl.java:117)

at org.jivesoftware.openfire.net.SASLAuthentication.handle(SASLAuthentication.java :274)

at org.jivesoftware.openfire.SessionPacketRouter.route(SessionPacketRouter.java:66 )

at org.jivesoftware.openfire.http.HttpSession.sendPendingPackets(HttpSession.java: 636)

at org.jivesoftware.openfire.http.HttpSessionManager$HttpPacketSender.run(HttpSess ionManager.java:390)

at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)

at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)

at java.lang.Thread.run(Unknown Source)

Exception in thread “pool-10-thread-10” java.lang.AbstractMethodError

at org.jivesoftware.openfire.event.SessionEventDispatcher.dispatchEvent(SessionEve ntDispatcher.java:90)

at org.jivesoftware.openfire.handler.IQBindHandler.handleIQ(IQBindHandler.java:161 )

at org.jivesoftware.openfire.handler.IQHandler.process(IQHandler.java:65)

at org.jivesoftware.openfire.IQRouter.handle(IQRouter.java:372)

at org.jivesoftware.openfire.IQRouter.route(IQRouter.java:121)

at org.jivesoftware.openfire.spi.PacketRouterImpl.route(PacketRouterImpl.java:76)

at org.jivesoftware.openfire.SessionPacketRouter.route(SessionPacketRouter.java:10 8)

at org.jivesoftware.openfire.SessionPacketRouter.route(SessionPacketRouter.java:69 )

at org.jivesoftware.openfire.http.HttpSession.sendPendingPackets(HttpSession.java: 636)

at org.jivesoftware.openfire.http.HttpSessionManager$HttpPacketSender.run(HttpSess ionManager.java:390)

at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)

at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)

at java.lang.Thread.run(Unknown Source)