DiscordBotAPI error?!

[19:38:46] [Server thread/ERROR]: Could not load 'plugins/SpigotBot.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.NoClassDefFoundError: com/tjplaysnow/discord/object/ProgramThread
    at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:135) ~[spigot.jar:git-Spigot-db6de12-18fbb24]
    at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:329) ~[spigot.jar:git-Spigot-db6de12-18fbb24]
    at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:251) [spigot.jar:git-Spigot-db6de12-18fbb24]
    at org.bukkit.craftbukkit.v1_8_R3.CraftServer.loadPlugins(CraftServer.java:292) [spigot.jar:git-Spigot-db6de12-18fbb24]
    at net.minecraft.server.v1_8_R3.DedicatedServer.init(DedicatedServer.java:198) [spigot.jar:git-Spigot-db6de12-18fbb24]
    at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:525) [spigot.jar:git-Spigot-db6de12-18fbb24]
    at java.lang.Thread.run(Thread.java:748) [?:1.8.0_292]
Caused by: java.lang.NoClassDefFoundError: com/tjplaysnow/discord/object/ProgramThread
    at java.lang.Class.forName0(Native Method) ~[?:1.8.0_292]
    at java.lang.Class.forName(Class.java:348) ~[?:1.8.0_292]
    at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.java:64) ~[spigot.jar:git-Spigot-db6de12-18fbb24]
    at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:131) ~[spigot.jar:git-Spigot-db6de12-18fbb24]
    ... 6 more
Caused by: java.lang.ClassNotFoundException: com.tjplaysnow.discord.object.ProgramThread
    at java.net.URLClassLoader.findClass(URLClassLoader.java:382) ~[?:1.8.0_292]
    at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:101) ~[spigot.jar:git-Spigot-db6de12-18fbb24]
    at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:86) ~[spigot.jar:git-Spigot-db6de12-18fbb24]
    at java.lang.ClassLoader.loadClass(ClassLoader.java:418) ~[?:1.8.0_292]
    at java.lang.ClassLoader.loadClass(ClassLoader.java:351) ~[?:1.8.0_292]
    at java.lang.Class.forName0(Native Method) ~[?:1.8.0_292]
    at java.lang.Class.forName(Class.java:348) ~[?:1.8.0_292]
    at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.java:64) ~[spigot.jar:git-Spigot-db6de12-18fbb24]
    at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:131) ~[spigot.jar:git-Spigot-db6de12-18fbb24]
    ... 6 more