Bukkit

What steps will reproduce the problem?
1. using 1.27
2. using 1.26
3. try it several times

What is the expected output? What do you see instead?
Using with bukkit 1.7.2 r0.3 tested with 1.27 and then try with 1.26. still getting errors

02:48:18 [SEVERE] Error occurred while enabling ChgUsers v1.26 (Is it up to date?) 02:48:18 java.lang.NoClassDefFoundError: net/citizensnpcs/Citizens 02:48:18 at me.bibo38.ChgUsers.ChgUsers.onEnable(Unknown Source) [?:?] 02:48:18 at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:250) [craftbukkit-1.7.2.jar:git-Bukkit-1.7.2-R0.3-b3020jnks] 02:48:18 at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:350) [craftbukkit-1.7.2.jar:git-Bukkit-1.7.2-R0.3-b3020jnks] 02:48:18 at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:389) [craftbukkit-1.7.2.jar:git-Bukkit-1.7.2-R0.3-b3020jnks] 02:48:18 at org.bukkit.craftbukkit.v1_7_R1.CraftServer.loadPlugin(CraftServer.java:439) [craftbukkit-1.7.2.jar:git-Bukkit-1.7.2-R0.3-b3020jnks] 02:48:18 at org.bukkit.craftbukkit.v1_7_R1.CraftServer.enablePlugins(CraftServer.java:375) [craftbukkit-1.7.2.jar:git-Bukkit-1.7.2-R0.3-b3020jnks] 02:48:18 at net.minecraft.server.v1_7_R1.MinecraftServer.m(MinecraftServer.java:342) [craftbukkit-1.7.2.jar:git-Bukkit-1.7.2-R0.3-b3020jnks] 02:48:18 at net.minecraft.server.v1_7_R1.MinecraftServer.g(MinecraftServer.java:319) [craftbukkit-1.7.2.jar:git-Bukkit-1.7.2-R0.3-b3020jnks] 02:48:18 at net.minecraft.server.v1_7_R1.MinecraftServer.a(MinecraftServer.java:275) [craftbukkit-1.7.2.jar:git-Bukkit-1.7.2-R0.3-b3020jnks] 02:48:18 at net.minecraft.server.v1_7_R1.DedicatedServer.init(DedicatedServer.java:175) [craftbukkit-1.7.2.jar:git-Bukkit-1.7.2-R0.3-b3020jnks] 02:48:18 at net.minecraft.server.v1_7_R1.MinecraftServer.run(MinecraftServer.java:424) [craftbukkit-1.7.2.jar:git-Bukkit-1.7.2-R0.3-b3020jnks] 02:48:18 at net.minecraft.server.v1_7_R1.ThreadServerApplication.run(SourceFile:617) [craftbukkit-1.7.2.jar:git-Bukkit-1.7.2-R0.3-b3020jnks] 02:48:18 Caused by: java.lang.ClassNotFoundException: net.citizensnpcs.Citizens 02:48:18 at java.net.URLClassLoader$1.run(Unknown Source) [?:1.7.0_51] 02:48:18 at java.net.URLClassLoader$1.run(Unknown Source) [?:1.7.0_51] 02:48:18 at java.security.AccessController.doPrivileged(Native Method) [?:1.7.0_51] 02:48:18 at java.net.URLClassLoader.findClass(Unknown Source) [?:1.7.0_51] 02:48:18 at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:77) [craftbukkit-1.7.2.jar:git-Bukkit-1.7.2-R0.3-b3020jnks] 02:48:18 at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:62) [craftbukkit-1.7.2.jar:git-Bukkit-1.7.2-R0.3-b3020jnks] 02:48:18 at java.lang.ClassLoader.loadClass(Unknown Source) [?:1.7.0_51] 02:48:18 at java.lang.ClassLoader.loadClass(Unknown Source) [?:1.7.0_51] 02:48:18 ... 12 more

What version of the product are you using?
1.27 1.26

Do you have an error log of what happened?
Using with bukkit 1.7.2 r0.3 tested with 1.27 and then try with 1.26. still getting errors

02:48:18 [SEVERE] Error occurred while enabling ChgUsers v1.26 (Is it up to date?) 02:48:18 java.lang.NoClassDefFoundError: net/citizensnpcs/Citizens 02:48:18 at me.bibo38.ChgUsers.ChgUsers.onEnable(Unknown Source) [?:?] 02:48:18 at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:250) [craftbukkit-1.7.2.jar:git-Bukkit-1.7.2-R0.3-b3020jnks] 02:48:18 at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:350) [craftbukkit-1.7.2.jar:git-Bukkit-1.7.2-R0.3-b3020jnks] 02:48:18 at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:389) [craftbukkit-1.7.2.jar:git-Bukkit-1.7.2-R0.3-b3020jnks] 02:48:18 at org.bukkit.craftbukkit.v1_7_R1.CraftServer.loadPlugin(CraftServer.java:439) [craftbukkit-1.7.2.jar:git-Bukkit-1.7.2-R0.3-b3020jnks] 02:48:18 at org.bukkit.craftbukkit.v1_7_R1.CraftServer.enablePlugins(CraftServer.java:375) [craftbukkit-1.7.2.jar:git-Bukkit-1.7.2-R0.3-b3020jnks] 02:48:18 at net.minecraft.server.v1_7_R1.MinecraftServer.m(MinecraftServer.java:342) [craftbukkit-1.7.2.jar:git-Bukkit-1.7.2-R0.3-b3020jnks] 02:48:18 at net.minecraft.server.v1_7_R1.MinecraftServer.g(MinecraftServer.java:319) [craftbukkit-1.7.2.jar:git-Bukkit-1.7.2-R0.3-b3020jnks] 02:48:18 at net.minecraft.server.v1_7_R1.MinecraftServer.a(MinecraftServer.java:275) [craftbukkit-1.7.2.jar:git-Bukkit-1.7.2-R0.3-b3020jnks] 02:48:18 at net.minecraft.server.v1_7_R1.DedicatedServer.init(DedicatedServer.java:175) [craftbukkit-1.7.2.jar:git-Bukkit-1.7.2-R0.3-b3020jnks] 02:48:18 at net.minecraft.server.v1_7_R1.MinecraftServer.run(MinecraftServer.java:424) [craftbukkit-1.7.2.jar:git-Bukkit-1.7.2-R0.3-b3020jnks] 02:48:18 at net.minecraft.server.v1_7_R1.ThreadServerApplication.run(SourceFile:617) [craftbukkit-1.7.2.jar:git-Bukkit-1.7.2-R0.3-b3020jnks] 02:48:18 Caused by: java.lang.ClassNotFoundException: net.citizensnpcs.Citizens 02:48:18 at java.net.URLClassLoader$1.run(Unknown Source) [?:1.7.0_51] 02:48:18 at java.net.URLClassLoader$1.run(Unknown Source) [?:1.7.0_51] 02:48:18 at java.security.AccessController.doPrivileged(Native Method) [?:1.7.0_51] 02:48:18 at java.net.URLClassLoader.findClass(Unknown Source) [?:1.7.0_51] 02:48:18 at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:77) [craftbukkit-1.7.2.jar:git-Bukkit-1.7.2-R0.3-b3020jnks] 02:48:18 at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:62) [craftbukkit-1.7.2.jar:git-Bukkit-1.7.2-R0.3-b3020jnks] 02:48:18 at java.lang.ClassLoader.loadClass(Unknown Source) [?:1.7.0_51] 02:48:18 at java.lang.ClassLoader.loadClass(Unknown Source) [?:1.7.0_51] 02:48:18 ... 12 more

Please provide any additional information below.
on start up