17:58:08 [SEVERE] Error occurred while enabling Lift v11 (Is it up to date?)
java.lang.IllegalArgumentException: No enum constant org.bukkit.Material.LAPIS_LAZULI_BLOCK
at java.lang.Enum.valueOf(Unknown Source)
at org.bukkit.Material.valueOf(Material.java:20)
at net.croxis.plugins.lift.Lift.onEnable(Lift.java:47)
at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:215)
at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:336)
at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:363)
at org.bukkit.craftbukkit.CraftServer.loadPlugin(CraftServer.java:250)
at org.bukkit.craftbukkit.CraftServer.enablePlugins(CraftServer.java:232)
at org.bukkit.craftbukkit.CraftServer.reload(CraftServer.java:539)
at org.bukkit.Bukkit.reload(Bukkit.java:182)
at org.bukkit.command.defaults.ReloadCommand.execute(ReloadCommand.java:22)
at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:166)
at org.bukkit.craftbukkit.CraftServer.dispatchCommand(CraftServer.java:469)
at net.minecraft.server.NetServerHandler.handleCommand(NetServerHandler.java:907)
at net.minecraft.server.NetServerHandler.chat(NetServerHandler.java:867)
at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:850)
at net.minecraft.server.Packet3Chat.handle(Packet3Chat.java:33)
at net.minecraft.server.NetworkManager.b(NetworkManager.java:229)
at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:116)
at net.minecraft.server.NetworkListenThread.a(NetworkListenThread.java:78)
at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:554)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:452)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:490)

Lift 11

version
18:21:35 [INFO] This server is running CraftBukkit version git-Bukkit-1.2.3-R0.2-38-gf6e6922-b2083jnks (MC: 1.2.3) (Implementing API version 1.2.3-R0.3-SNAPSHOT)

You need to use the correct material type: http://jd.bukkit.org/apidocs/org/bukkit/Material.html