LogWriter java.lang.NoSuchMethodError

hi !

after building the RI and using the jars in my application , I get the following
error : 


Caused by: java.lang.reflect.InvocationTargetException
	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:494)
	at javax.sip.SipFactory.createStack(SipFactory.java:304)
	... 8 more
Caused by: java.lang.NoSuchMethodError:
gov.nist.core.LogWriter.<init>(Ljava/util/Properties;)V
	at gov.nist.javax.sip.SipStackImpl.<init>(SipStackImpl.java:279)
	... 13 more 


any idea , what went wrong ?

stefan