Bukkit

It mentions PermissionsEX in the error, and just before this, I removed PEX and replaced it with zPermissions.

2013-07-10 09:23:21 [INFO] [LiftSign] Enabling LiftSign v0.2
2013-07-10 09:23:22 [SEVERE] Error occurred while enabling LiftSign v0.2 (Is it up to date?)
org.morganm.liftsign.guice.internal.util.$ComputationException: org.morganm.liftsign.guice.internal.util.$ComputationException: java.lang.NoClassDefFoundError: Lru/tehkode/permissions/bukkit/PermissionsEx;
    at org.morganm.liftsign.guice.internal.util.$MapMaker$StrategyImpl.compute(MapMaker.java:553)
    at org.morganm.liftsign.guice.internal.util.$MapMaker$StrategyImpl.compute(MapMaker.java:419)
    at org.morganm.liftsign.guice.internal.util.$CustomConcurrentHashMap$ComputingImpl.get(CustomConcurrentHashMap.java:2041)
    at org.morganm.liftsign.guice.internal.FailableCache.get(FailableCache.java:50)
    at org.morganm.liftsign.guice.internal.ConstructorInjectorStore.get(ConstructorInjectorStore.java:49)
    at org.morganm.liftsign.guice.internal.ConstructorBindingImpl.initialize(ConstructorBindingImpl.java:125)
    at org.morganm.liftsign.guice.internal.InjectorImpl.initializeBinding(InjectorImpl.java:507)
    at org.morganm.liftsign.guice.internal.AbstractBindingProcessor$Processor$1.run(AbstractBindingProcessor.java:159)
    at org.morganm.liftsign.guice.internal.ProcessedBindingData.initializeBindings(ProcessedBindingData.java:44)
    at org.morganm.liftsign.guice.internal.InternalInjectorCreator.initializeStatically(InternalInjectorCreator.java:122)
    at org.morganm.liftsign.guice.internal.InternalInjectorCreator.build(InternalInjectorCreator.java:106)
    at org.morganm.liftsign.guice.Guice.createInjector(Guice.java:95)
    at org.morganm.liftsign.guice.Guice.createInjector(Guice.java:72)
    at org.morganm.liftsign.guice.Guice.createInjector(Guice.java:62)
    at org.morganm.liftsign.LiftSign.onEnable(LiftSign.java:78)
    at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:217)
    at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:457)
    at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:381)
    at org.bukkit.craftbukkit.v1_6_R2.CraftServer.loadPlugin(CraftServer.java:282)
    at org.bukkit.craftbukkit.v1_6_R2.CraftServer.enablePlugins(CraftServer.java:264)
    at net.minecraft.server.v1_6_R2.MinecraftServer.l(MinecraftServer.java:313)
    at net.minecraft.server.v1_6_R2.MinecraftServer.f(MinecraftServer.java:290)
    at net.minecraft.server.v1_6_R2.MinecraftServer.a(MinecraftServer.java:250)
    at net.minecraft.server.v1_6_R2.DedicatedServer.init(DedicatedServer.java:151)
    at net.minecraft.server.v1_6_R2.MinecraftServer.run(MinecraftServer.java:391)
    at net.minecraft.server.v1_6_R2.ThreadServerApplication.run(SourceFile:582)
Caused by: org.morganm.liftsign.guice.internal.util.$ComputationException: java.lang.NoClassDefFoundError: Lru/tehkode/permissions/bukkit/PermissionsEx;
    at org.morganm.liftsign.guice.internal.util.$MapMaker$StrategyImpl.compute(MapMaker.java:553)
    at org.morganm.liftsign.guice.internal.util.$MapMaker$StrategyImpl.compute(MapMaker.java:419)
    at org.morganm.liftsign.guice.internal.util.$CustomConcurrentHashMap$ComputingImpl.get(CustomConcurrentHashMap.java:2041)
    at org.morganm.liftsign.guice.internal.FailableCache.get(FailableCache.java:50)
    at org.morganm.liftsign.guice.internal.MembersInjectorStore.get(MembersInjectorStore.java:65)
    at org.morganm.liftsign.guice.internal.ConstructorInjectorStore.createConstructor(ConstructorInjectorStore.java:73)
    at org.morganm.liftsign.guice.internal.ConstructorInjectorStore.access$000(ConstructorInjectorStore.java:28)
    at org.morganm.liftsign.guice.internal.ConstructorInjectorStore$1.create(ConstructorInjectorStore.java:36)
    at org.morganm.liftsign.guice.internal.ConstructorInjectorStore$1.create(ConstructorInjectorStore.java:32)
    at org.morganm.liftsign.guice.internal.FailableCache$1.apply(FailableCache.java:39)
    at org.morganm.liftsign.guice.internal.util.$MapMaker$StrategyImpl.compute(MapMaker.java:549)
    ... 25 more
Caused by: java.lang.NoClassDefFoundError: Lru/tehkode/permissions/bukkit/PermissionsEx;
    at java.lang.Class.getDeclaredFields0(Native Method)
    at java.lang.Class.privateGetDeclaredFields(Unknown Source)
    at java.lang.Class.getDeclaredFields(Unknown Source)
    at org.morganm.liftsign.guice.spi.InjectionPoint.getInjectionPoints(InjectionPoint.java:649)
    at org.morganm.liftsign.guice.spi.InjectionPoint.forInstanceMethodsAndFields(InjectionPoint.java:356)
    at org.morganm.liftsign.guice.internal.MembersInjectorStore.createWithListeners(MembersInjectorStore.java:90)
    at org.morganm.liftsign.guice.internal.MembersInjectorStore.access$000(MembersInjectorStore.java:34)
    at org.morganm.liftsign.guice.internal.MembersInjectorStore$1.create(MembersInjectorStore.java:42)
    at org.morganm.liftsign.guice.internal.MembersInjectorStore$1.create(MembersInjectorStore.java:39)
    at org.morganm.liftsign.guice.internal.FailableCache$1.apply(FailableCache.java:39)
    at org.morganm.liftsign.guice.internal.util.$MapMaker$StrategyImpl.compute(MapMaker.java:549)
    ... 35 more
Caused by: java.lang.ClassNotFoundException: ru.tehkode.permissions.bukkit.PermissionsEx
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(Unknown Source)
    at org.bukkit.plugin.java.PluginClassLoader.findClass0(PluginClassLoader.java:80)
    at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:53)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    ... 46 more

Thank you for including the startup message, which shows:

2013-07-10 09:23:21 [INFO] [LiftSign] Enabling LiftSign v0.2
2013-07-10 09:23:22 [SEVERE] Error occurred while enabling LiftSign v0.2 (Is it up to date?)

Note the "is it up to date?" question. A quick check of the LiftSign Files page:

http://dev.bukkit.org/bukkit-plugins/liftsign/files/

Shows v0.3 was released Jan 4, 2013 (7 months ago). A quick check of the v0.3 changelog:

http://dev.bukkit.org/bukkit-plugins/liftsign/files/3-v0-3/

Shows this change/fix in that version:

• fix for reported issue with Vault/PEX

Please upgrade to v0.3 and let me know if you still see the error. I'm guessing no, since I just setup a test environment without PEX and it works fine with CraftBukkit 1.6.2 (latest dev) and LiftSign v0.3.