CONSOLE: ERROR]: Error occurred while enabling VoxelSniper v5.168.7-SNAPSHOT-jnks245 (Is it up to date?)
CONSOLE: Method) ~[?:1.7.0_25]
CONSOLE:
java.lang.ClassNotFoundException: net.minecraft.server.v1_6_R3.EntityLiving

This is too little information. Could you tell me which version the server is?

Im running this version of bukkit 1.7.2-R0.3

Also running latest version of VoxelSniper

this version VoxelSniper-5.168.7-SNAPSHOT.jar

Then you got the wrong VoxelSniper version, because the one you are using is build against 1.6.4. Make sure you have the latest from http://ci.thevoxelbox.com