Big Problem! Help me please!

Every time I turn on my server and wait a few seconds and a few people start playing this comes up

Code:

[client-2-hunter]: playerCommand: bank
java.lang.ArrayIndexOutOfBoundsException: 1000000
        at stream.writeDWord(stream.java:207)
        at client.addItem(client.java:13880)
        at client.fromBank(client.java:12791)
        at client.parseIncomingPackets(client.java:21462)
        at client.packetProcess(client.java:16369)
        at client.process(client.java:16339)
        at PlayerHandler.process(PlayerHandler.java:137)
        at server.main(server.java:50)
Project16 [fatal] - exception
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 1000001
        at stream.createFrameVarSizeWord(stream.java:168)
        at client.sendQuest(client.java:9003)
        at client.process(client.java:14987)
        at PlayerHandler.process(PlayerHandler.java:137)
        at server.main(server.java:50)

Does anyone know what it is?
Please help me a.s.a.p.
Thanks

 

Someone may be trying to spawn items with huge Integers.