[20:22:30 WARN]: [FallingTrees] Task #519 for FallingTrees v1.2 generated an exc
eption
java.lang.NoClassDefFoundError: net/minecraft/server/v1_7_R1/MathHelper
        at me.corperateraider.fallingtrees.TreeRunnable.tick(TreeListener.java:9
0) ~[?:?]
        at me.corperateraider.fallingtrees.TreeListener.run(TreeListener.java:41
) ~[?:?]
        at org.bukkit.craftbukkit.v1_8_R2.scheduler.CraftTask.run(CraftTask.java
:71) ~[spigot-1.8.3.jar:git-Spigot-dbe012b-61ef214]
        at org.bukkit.craftbukkit.v1_8_R2.scheduler.CraftScheduler.mainThreadHea
rtbeat(CraftScheduler.java:350) [spigot-1.8.3.jar:git-Spigot-dbe012b-61ef214]
        at net.minecraft.server.v1_8_R2.MinecraftServer.A(MinecraftServer.java:7
18) [spigot-1.8.3.jar:git-Spigot-dbe012b-61ef214]
        at net.minecraft.server.v1_8_R2.DedicatedServer.A(DedicatedServer.java:3
68) [spigot-1.8.3.jar:git-Spigot-dbe012b-61ef214]
        at net.minecraft.server.v1_8_R2.MinecraftServer.z(MinecraftServer.java:6
51) [spigot-1.8.3.jar:git-Spigot-dbe012b-61ef214]
        at net.minecraft.server.v1_8_R2.MinecraftServer.run(MinecraftServer.java
:554) [spigot-1.8.3.jar:git-Spigot-dbe012b-61ef214]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_40]