[15:02:14] [Server thread/ERROR]: Encountered an unexpected exception
java.lang.RuntimeException: Error generating crash report
at net.minecraft.server.v1_7_R1.MinecraftServer.u(MinecraftServer.java:679) ~[mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at net.minecraft.server.v1_7_R1.DedicatedServer.u(DedicatedServer.java:273) ~[mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at net.minecraft.server.v1_7_R1.MinecraftServer.t(MinecraftServer.java:562) ~[mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at net.minecraft.server.v1_7_R1.MinecraftServer.run(MinecraftServer.java:469) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at net.minecraft.server.v1_7_R1.ThreadServerApplication.run(SourceFile:617) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
Caused by: java.lang.OutOfMemoryError: PermGen space
at net.minecraft.server.v1_7_R1.MinecraftServer.u(MinecraftServer.java:677) ~[mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
... 4 more
[15:02:14] [Server thread/ERROR]:  Cause of unexpected exception was
java.lang.OutOfMemoryError: PermGen space
at net.minecraft.server.v1_7_R1.MinecraftServer.u(MinecraftServer.java:677) ~[mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at net.minecraft.server.v1_7_R1.DedicatedServer.u(DedicatedServer.java:273) ~[mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at net.minecraft.server.v1_7_R1.MinecraftServer.t(MinecraftServer.java:562) ~[mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at net.minecraft.server.v1_7_R1.MinecraftServer.run(MinecraftServer.java:469) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at net.minecraft.server.v1_7_R1.ThreadServerApplication.run(SourceFile:617) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
[15:02:15] [Server thread/INFO]: Stopping server
[15:02:15] [Server thread/INFO]: [EpicGuildRank] Disabling EpicGuildRank v1.0
[15:02:16] [Server thread/ERROR]: Could not pass event PluginDisableEvent to MyPet v1.1.7
org.bukkit.event.EventException
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:322) ~[mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at org.bukkit.plugin.TimedRegisteredListener.callEvent(TimedRegisteredListener.java:30) ~[mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:487) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:472) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at org.bukkit.plugin.java.JavaPluginLoader.disablePlugin(JavaPluginLoader.java:368) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at org.bukkit.plugin.SimplePluginManager.disablePlugin(SimplePluginManager.java:409) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at org.bukkit.plugin.SimplePluginManager.disablePlugins(SimplePluginManager.java:402) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at org.bukkit.craftbukkit.v1_7_R1.CraftServer.disablePlugins(CraftServer.java:398) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at net.minecraft.server.v1_7_R1.MinecraftServer.stop(MinecraftServer.java:381) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at net.minecraft.server.v1_7_R1.MinecraftServer.run(MinecraftServer.java:504) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at net.minecraft.server.v1_7_R1.ThreadServerApplication.run(SourceFile:617) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
Caused by: java.lang.OutOfMemoryError: PermGen space
[15:02:17] [Server thread/ERROR]: Could not pass event PluginDisableEvent to MyPet v1.1.7
org.bukkit.event.EventException
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:322) ~[mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at org.bukkit.plugin.TimedRegisteredListener.callEvent(TimedRegisteredListener.java:30) ~[mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:487) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:472) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at org.bukkit.plugin.java.JavaPluginLoader.disablePlugin(JavaPluginLoader.java:368) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at org.bukkit.plugin.SimplePluginManager.disablePlugin(SimplePluginManager.java:409) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at org.bukkit.plugin.SimplePluginManager.disablePlugins(SimplePluginManager.java:402) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at org.bukkit.craftbukkit.v1_7_R1.CraftServer.disablePlugins(CraftServer.java:398) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at net.minecraft.server.v1_7_R1.MinecraftServer.stop(MinecraftServer.java:381) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at net.minecraft.server.v1_7_R1.MinecraftServer.run(MinecraftServer.java:504) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at net.minecraft.server.v1_7_R1.ThreadServerApplication.run(SourceFile:617) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
Caused by: java.lang.OutOfMemoryError: PermGen space
[15:02:18] [Server thread/ERROR]: Could not pass event PluginDisableEvent to MyPet v1.1.7
org.bukkit.event.EventException
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:322) ~[mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at org.bukkit.plugin.TimedRegisteredListener.callEvent(TimedRegisteredListener.java:30) ~[mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:487) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:472) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at org.bukkit.plugin.java.JavaPluginLoader.disablePlugin(JavaPluginLoader.java:368) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at org.bukkit.plugin.SimplePluginManager.disablePlugin(SimplePluginManager.java:409) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at org.bukkit.plugin.SimplePluginManager.disablePlugins(SimplePluginManager.java:402) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at org.bukkit.craftbukkit.v1_7_R1.CraftServer.disablePlugins(CraftServer.java:398) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at net.minecraft.server.v1_7_R1.MinecraftServer.stop(MinecraftServer.java:381) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at net.minecraft.server.v1_7_R1.MinecraftServer.run(MinecraftServer.java:504) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
at net.minecraft.server.v1_7_R1.ThreadServerApplication.run(SourceFile:617) [mc.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]
Caused by: java.lang.OutOfMemoryError: PermGen space
[15:02:18] [Server thread/INFO]: [AncientGates] Disabling AncientGates v1.8.0
[15:02:19] [Server thread/INFO]: [AncientGates v1.8.0] Disabled

内存溢出了，建议将服务端内存调大点
如果内存不够用了的话可以加插件来降低内存的使用
比如http://www.mcbbs.net/thread-603072-1-1.html
或者对服务端做一些优化http://www.mcbbs.net/thread-478126-1-1.html

同时MyPet插件也出了问题，建议换一个版本试试

Caused by: java.lang.OutOfMemoryError: PermGen space
内存溢出
加大内存吧