You have a multiability installed. remove any multiabilities from the multiabilities folder in the projectkorra folder.
I did as you said and I still get this...
[17:22:03] [Server thread/INFO]: [ProjectKorra] Enabling ProjectKorra v1.7.0 BETA 12
[17:22:04] [Server thread/ERROR]: Error occurred while enabling ProjectKorra v1.7.0 BETA 12 (Is it up to date?)
java.lang.NoClassDefFoundError: com/rockmc/korra/multiabilitymodule/MultiAbilityModule
at java.lang.ClassLoader.defineClass1(Native Method) ~[?:1.8.0_51]
at java.lang.ClassLoader.defineClass(Unknown Source) ~[?:1.8.0_51]
at java.security.SecureClassLoader.defineClass(Unknown Source) ~[?:1.8.0_51]
at java.net.URLClassLoader.defineClass(Unknown Source) ~[?:1.8.0_51]
at java.net.URLClassLoader.access$100(Unknown Source) ~[?:1.8.0_51]
at java.net.URLClassLoader$1.run(Unknown Source) ~[?:1.8.0_51]
at java.net.URLClassLoader$1.run(Unknown Source) ~[?:1.8.0_51]
at java.security.AccessController.doPrivileged(Native Method) ~[?:1.8.0_51]
at java.net.URLClassLoader.findClass(Unknown Source) ~[?:1.8.0_51]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_51]
at java.net.FactoryURLClassLoader.loadClass(Unknown Source) ~[?:1.8.0_51]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_51]
at java.lang.Class.forName0(Native Method) ~[?:1.8.0_51]
at java.lang.Class.forName(Unknown Source) ~[?:1.8.0_51]
at com.projectkorra.ProjectKorra.Utilities.AbilityLoader.load(AbilityLoader.java:84) ~[?:?]
at com.projectkorra.ProjectKorra.Ability.AbilityModuleManager.<init>(AbilityModuleManager.java:72) ~[?:?]
at com.projectkorra.ProjectKorra.ProjectKorra.onEnable(ProjectKorra.java:52) ~[?:?]
at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:321) ~[spigot.jar:git-Spigot-6d16e64-3d5ab8f]
at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:340) [spigot.jar:git-Spigot-6d16e64-3d5ab8f]
at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:405) [spigot.jar:git-Spigot-6d16e64-3d5ab8f]
at org.bukkit.craftbukkit.v1_8_R3.CraftServer.loadPlugin(CraftServer.java:356) [spigot.jar:git-Spigot-6d16e64-3d5ab8f]
at org.bukkit.craftbukkit.v1_8_R3.CraftServer.enablePlugins(CraftServer.java:316) [spigot.jar:git-Spigot-6d16e64-3d5ab8f]
at net.minecraft.server.v1_8_R3.MinecraftServer.s(MinecraftServer.java:414) [spigot.jar:git-Spigot-6d16e64-3d5ab8f]
at net.minecraft.server.v1_8_R3.MinecraftServer.k(MinecraftServer.java:378) [spigot.jar:git-Spigot-6d16e64-3d5ab8f]
at net.minecraft.server.v1_8_R3.MinecraftServer.a(MinecraftServer.java:333) [spigot.jar:git-Spigot-6d16e64-3d5ab8f]
at net.minecraft.server.v1_8_R3.DedicatedServer.init(DedicatedServer.java:263) [spigot.jar:git-Spigot-6d16e64-3d5ab8f]
at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:524) [spigot.jar:git-Spigot-6d16e64-3d5ab8f]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_51]
Caused by: java.lang.ClassNotFoundException: com.rockmc.korra.multiabilitymodule.MultiAbilityModule
at java.net.URLClassLoader.findClass(Unknown Source) ~[?:1.8.0_51]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_51]
at java.net.FactoryURLClassLoader.loadClass(Unknown Source) ~[?:1.8.0_51]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_51]
... 28 more
[17:22:04] [Server thread/INFO]: [JedCore] Enabling JedCore v1.1.4c
[17:22:04] [Server thread/INFO]: [JedCore] ###### Loading Abilities! ######
[17:22:04] [Server thread/ERROR]: Error occurred while enabling JedCore v1.1.4c (Is it up to date?)
java.lang.NullPointerException
at com.jedk1.JedCore.ability.JCoreAbilityManager.loadCustomAbilities(JCoreAbilityManager.java:57) ~[?:?]
at com.jedk1.JedCore.ability.JCoreAbilityManager.<init>(JCoreAbilityManager.java:43) ~[?:?]
at com.jedk1.JedCore.JedCore.onEnable(JedCore.java:33) ~[?:?]
at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:321) ~[spigot.jar:git-Spigot-6d16e64-3d5ab8f]
at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:340) [spigot.jar:git-Spigot-6d16e64-3d5ab8f]
at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:405) [spigot.jar:git-Spigot-6d16e64-3d5ab8f]
at org.bukkit.craftbukkit.v1_8_R3.CraftServer.loadPlugin(CraftServer.java:356) [spigot.jar:git-Spigot-6d16e64-3d5ab8f]
at org.bukkit.craftbukkit.v1_8_R3.CraftServer.enablePlugins(CraftServer.java:316) [spigot.jar:git-Spigot-6d16e64-3d5ab8f]
at net.minecraft.server.v1_8_R3.MinecraftServer.s(MinecraftServer.java:414) [spigot.jar:git-Spigot-6d16e64-3d5ab8f]
at net.minecraft.server.v1_8_R3.MinecraftServer.k(MinecraftServer.java:378) [spigot.jar:git-Spigot-6d16e64-3d5ab8f]
at net.minecraft.server.v1_8_R3.MinecraftServer.a(MinecraftServer.java:333) [spigot.jar:git-Spigot-6d16e64-3d5ab8f]
at net.minecraft.server.v1_8_R3.DedicatedServer.init(DedicatedServer.java:263) [spigot.jar:git-Spigot-6d16e64-3d5ab8f]
at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:524) [spigot.jar:git-Spigot-6d16e64-3d5ab8f]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_51]
[17:22:04]