exception in storm nimbus when accessing storm ui

gistfile1.java

2012-08-11 21:15:46 TNonblockingServer [ERROR] Unexpected exception while invoking!
java.lang.RuntimeException: java.lang.NullPointerException
	at clojure.lang.LazySeq.sval(LazySeq.java:47)
	at clojure.lang.LazySeq.seq(LazySeq.java:56)
	at clojure.lang.RT.seq(RT.java:450)
	at clojure.core$seq.invoke(core.clj:122)
	at clojure.core$dorun.invoke(core.clj:2450)
	at clojure.core$doall.invoke(core.clj:2465)
	at backtype.storm.daemon.nimbus$fn__3108$exec_fn__1021__auto__$reify__3126.getClusterInfo(nimbus.clj:770)
	at backtype.storm.generated.Nimbus$Processor$getClusterInfo.getResult(Nimbus.java:1223)
	at backtype.storm.generated.Nimbus$Processor$getClusterInfo.getResult(Nimbus.java:1212)
	at org.apache.thrift7.ProcessFunction.process(ProcessFunction.java:32)
	at org.apache.thrift7.TBaseProcessor.process(TBaseProcessor.java:34)
	at org.apache.thrift7.server.TNonblockingServer$FrameBuffer.invoke(TNonblockingServer.java:632)
	at org.apache.thrift7.server.THsHaServer$Invocation.run(THsHaServer.java:201)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
	at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.NullPointerException
	at clojure.core$name.invoke(core.clj:1245)
	at backtype.storm.daemon.nimbus$extract_status_str.invoke(nimbus.clj:555)
	at backtype.storm.daemon.nimbus$fn__3108$exec_fn__1021__auto__$reify__3126$iter__3152__3156$fn__3157.invoke(nimbus.clj:782)
	at clojure.lang.LazySeq.sval(LazySeq.java:42)
	... 15 more