Minecraft FML java error

[snizzit]

So, my server wont start because of a FML java error...


A problem occurred running the Server launcher.
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at cpw.mods.fml.relauncher.ServerLaunchWrapper.run(ServerLaunchWrapper.java:43)
at cpw.mods.fml.relauncher.ServerLaunchWrapper.main(ServerLaunchWrapper.java:12)
Caused by: java.lang.NoClassDefFoundError: org/apache/logging/log4j/Level
at net.minecraft.launchwrapper.Launch.launch(Launch.java:94)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)

Would anyone know how to resolve this so my server will start up using the forge 1.7.10 jar file so my mods will run?