Bukkit

[SEVERE] Could not load 'plugins/Showcase.jar' in folder 'plugins':
mapping values are not allowed here
in "<reader>", line 12, column 12:
          usage: |
               ^

    at org.yaml.snakeyaml.scanner.ScannerImpl.fetchValue(ScannerImpl.java:745)
    at org.yaml.snakeyaml.scanner.ScannerImpl.fetchMoreTokens(ScannerImpl.java:307)
    at org.yaml.snakeyaml.scanner.ScannerImpl.checkToken(ScannerImpl.java:183)
    at org.yaml.snakeyaml.parser.ParserImpl$ParseBlockMappingKey.produce(ParserImpl.java:564)
    at org.yaml.snakeyaml.parser.ParserImpl.peekEvent(ParserImpl.java:163)
    at org.yaml.snakeyaml.parser.ParserImpl.checkEvent(ParserImpl.java:148)
    at org.yaml.snakeyaml.composer.Composer.composeMappingNode(Composer.java:228)
    at org.yaml.snakeyaml.composer.Composer.composeNode(Composer.java:160)
    at org.yaml.snakeyaml.composer.Composer.composeMappingNode(Composer.java:230)
    at org.yaml.snakeyaml.composer.Composer.composeNode(Composer.java:160)
    at org.yaml.snakeyaml.composer.Composer.composeMappingNode(Composer.java:230)
    at org.yaml.snakeyaml.composer.Composer.composeNode(Composer.java:160)
    at org.yaml.snakeyaml.composer.Composer.composeDocument(Composer.java:122)
    at org.yaml.snakeyaml.composer.Composer.getSingleNode(Composer.java:105)
    at org.yaml.snakeyaml.constructor.BaseConstructor.getSingleData(BaseConstructor.java:124)
    at org.yaml.snakeyaml.Yaml.load(Yaml.java:264)
    at org.yaml.snakeyaml.Yaml.load(Yaml.java:250)
    at org.bukkit.plugin.PluginDescriptionFile.<init>(PluginDescriptionFile.java:39)
    at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:69)
    at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:213)
    at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:136)
    at org.bukkit.craftbukkit.CraftServer.loadPlugins(CraftServer.java:138)
    at org.bukkit.craftbukkit.CraftServer.<init>(CraftServer.java:103)
    at net.minecraft.server.ServerConfigurationManager.<init>(ServerConfigurationManager.java:52)
    at net.minecraft.server.MinecraftServer.init(MinecraftServer.java:136)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:348)
    at net.minecraft.server.ThreadServerApplication.run(SourceFile:417)