NPE in pim-Log

we are running GMS 3.0.1 on SLES 10 SP2 and get every 2 minutes the
following Null Pointer Exception in the pim-Log:

E 01:58:16:486 21950a Unexpected failure detected: NullPointerException
D 01:58:16:487 21950a java.lang.NullPointerException
at
java.util.EnumMap.typeCheck(EnumMap.java:656)
at java.util.EnumMap.put(EnumMap.java:241)
at
gwtranslator.GWEventCache.getEventList(GWEventCach e.java:101)
at
gwtranslator.GWEventCache.addEvent(GWEventCache.ja va:113)
at
gwtranslator.GWEventCache.AddEvent(GWEventCache.ja va:42)
at
gwtranslator.GWEvents.buildCacheAndDetermineFolder sToSync(GWEvents.java:1032
)
at
gwtranslator.GWEvents.processEvents(GWEvents.java: 564)
at
gwtranslator.GWEvents.processEvents(GWEvents.java: 378)
at
gwtranslator.GWEvents.loadEvents(GWEvents.java:278 )
at
gwtranslator.GWNotificationConnection.doProcessEve nt(GWNotificationConnectio
n.java:371)
at
gwtranslator.GWNotificationConnection.processEvent (GWNotificationConnection.
java:324)
at
gwtranslator.GWNotificationConnection.processNotif ication(GWNotificationConn
ection.java:422)
at
gwtranslator.GWNotificationConnection.run(GWNotifi cationConnection.java:209)

at
util.ThreadPool$PoolThread.run(ThreadPool.java:62)

any ideas what goes wrong?

Thanks
Andrej