Recent changes (probably involving the vector stuff) mean that we get this error when running without WorldEdit:

[SEVERE] Could not load 'plugins\OtherBlocks.jar' in folder 'plugins':
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:173)
at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:207)
at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:130)
at org.bukkit.craftbukkit.CraftServer.loadPlugins(CraftServer.java:128)
at org.bukkit.craftbukkit.CraftServer.(CraftServer.java:97)
at net.minecraft.server.ServerConfigurationManager.(ServerConfigurationManager.java:51)
at net.minecraft.server.MinecraftServer.init(MinecraftServer.java:132)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:335)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:422)
Caused by: java.lang.NoClassDefFoundError: com/sk89q/worldedit/Vector
at com.gmail.zariust.bukkit.otherblocks.OtherBlocks.(OtherBlocks.java:180)
... 13 more
Caused by: java.lang.ClassNotFoundException: com.sk89q.worldedit.Vector
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:36)
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:24)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 14 more

Fixed in final 1.9 release