My server runs for a few good hours and then sometimes by itself it shuts down. I just come back to the station where it's hosted and the command prompt is gone. According to this website http://canihostaminecraftserver.com/ I can host 27 people including myself although my server is set to 20. Although I do have quite a lot of plugins: AntiXray, bPermissions, ChestShop, ClearLag, DrugMeUp, Enjin(It checks if my server is online or offline), eTeleport, Grief Prevention, Hoams, iConomy, Inventory, Multiverse-Core, Multiverse-Portal, Punish Control, SimpleServerAnnounce, SpawnPlus, and Warp. I'm running bukkit 1.4.7-R1 on Minecraft 1.5.1. The server is set to 3 GB of ram. I have windows 7 64 Bit version. The version of my Java is 7 update 17. Any help is greatly appreciated.