InstanceAlreadyExistsException

Was testing out 05 last night, and got this error, can't boot up a node because of it. I'll be happy to debug if more info is needed, it's quite late here.

ERROR [main] 2009-12-22 21:52:14,167 StorageService.java (line 129) Exception was generated at : 12/22/2009 21:52:14 on thread main
javax.management.InstanceAlreadyExistsException: org.apache.cassandra.concurrent:type=CONSISTENCY-MANAGER
java.lang.RuntimeException: javax.management.InstanceAlreadyExistsException: org.apache.cassandra.concurrent:type=CONSISTENCY-MANAGER
at org.apache.cassandra.concurrent.DebuggableThreadPoolExecutor.<init>(DebuggableThreadPoolExecutor.java:63)
at org.apache.cassandra.service.StorageService.<init>(StorageService.java:151)
at org.apache.cassandra.service.StorageService.instance(StorageService.java:125)
at org.apache.cassandra.locator.RackAwareStrategy.<init>(RackAwareStrategy.java:47)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at org.apache.cassandra.service.StorageService.getReplicationStrategy(StorageService.java:244)
at org.apache.cassandra.service.StorageService.<init>(StorageService.java:233)
at org.apache.cassandra.service.StorageService.instance(StorageService.java:125)
at org.apache.cassandra.service.CassandraServer.<init>(CassandraServer.java:58)
at org.apache.cassandra.service.CassandraDaemon.setup(CassandraDaemon.java:93)
at org.apache.cassandra.service.CassandraDaemon.init(CassandraDaemon.java:135)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.commons.daemon.support.DaemonLoader.load(DaemonLoader.java:160)
Caused by: javax.management.InstanceAlreadyExistsException: org.apache.cassandra.concurrent:type=CONSISTENCY-MANAGER
at com.sun.jmx.mbeanserver.Repository.addMBean(Repository.java:453)
at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.internal_addObject(DefaultMBeanServerInterceptor.java:1484)
at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerDynamicMBean(DefaultMBeanServerInterceptor.java:963)
at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerObject(DefaultMBeanServerInterceptor.java:917)
at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerMBean(DefaultMBeanServerInterceptor.java:312)
at com.sun.jmx.mbeanserver.JmxMBeanServer.registerMBean(JmxMBeanServer.java:482)
at org.apache.cassandra.concurrent.DebuggableThreadPoolExecutor.<init>(DebuggableThreadPoolExecutor.java:59)
... 18 more