this is a pvp arena i made,no help.make sure the server properties is the same thing as below:
generator-settings= allow-nether=true level-name=xtreme pvp enable-query=false allow-flight=false server-port=25565 level-type=DEFAULT enable-rcon=false level-seed= server-ip= max-build-height=256 spawn-npcs=false white-list=false spawn-animals=false snooper-enabled=true hardcore=true texture-pack= online-mode=false pvp=true difficulty=2 gamemode=2 max-players=30 spawn-monsters=false generate-structures=true view-distance=10 motd=A Minecraft Server spawn-protection=16