S4 status error due to invalid parsing

(from s4-dev mailing list, reported by Dingyu Yang):

I find a problem that I have a app ,which includes multiple streams. They
can merge into a stream, and a stream goes into multiple PEs.
Then the s4 status command can not display.
Cannot get the status of S4.

11:09:56.308 [main] ERROR org.apache.s4.tools.Status - Cannot get the
status of S4
java.util.FormatFlagsConversionMismatchException: Conversion = s, Flags = 0
at java.util.Formatter$FormatSpecifier.failMismatch(Formatter.java:3995)
~[na:1.6.0_22]
at java.util.Formatter$FormatSpecifier.checkBadFlags(Formatter.java:2905)
~[na:1.6.0_22]
at java.util.Formatter$FormatSpecifier.checkGeneral(Formatter.java:2863)
~[na:1.6.0_22]
at java.util.Formatter$FormatSpecifier.<init>(Formatter.java:2639)
~[na:1.6.0_22]
at java.util.Formatter.parse(Formatter.java:2480) ~[na:1.6.0_22]
at java.util.Formatter.format(Formatter.java:2414) ~[na:1.6.0_22]
at java.util.Formatter.format(Formatter.java:2367) ~[na:1.6.0_22]
at java.lang.String.format(String.java:2769) ~[na:1.6.0_22]
at org.apache.s4.tools.Status.inMiddle(Status.java:209)
~[s4-tools-0.5.0-incubating.jar:0.5.0-incubating]
at org.apache.s4.tools.Status.showStreamsStatus(Status.java:199)
~[s4-tools-0.5.0-incubating.jar:0.5.0-incubating]
at org.apache.s4.tools.Status.main(Status.java:119)
~[s4-tools-0.5.0-incubating.jar:0.5.0-incubating]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
~[na:1.6.0_22]
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
~[na:1.6.0_22]
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
~[na:1.6.0_22]
at java.lang.reflect.Method.invoke(Method.java:597) ~[na:1.6.0_22]
at org.apache.s4.tools.Tools$Task.dispatch(Tools.java:54)
[s4-tools-0.5.0-incubating.jar:0.5.0-incubating]
at org.apache.s4.tools.Tools.main(Tools.java:94)
[s4-tools-0.5.0-incubating.jar:0.5.0-incubating]