AbstractMethodError

[Craig Green]

Hello,
        My exception is:
Exception in thread "main" java.lang.AbstractMethodError
        at org.apache.soap.util.xml.QName.<init>(QName.java:80)
        at org.apache.soap.util.xml.QName.matches(QName.java:146)
        at org.apache.soap.Envelope.unmarshall(Envelope.java:237)
        at org.apache.soap.rpc.Call.invoke(Call.java:230)
        at com.bulldog.webservice.test.LoginTest.main(LoginTest.java:115)

my classpath contains (in this order):
xerces.jar v3.0.1,
soap.jar v2.2, 
mail.jar,
activation.jar,
parser.jar,
jaxp.jar,
+ my webapp files

Can anyone tell my why this exception is being thrown? I'm assuming I have
the wrong versions of some jars files. Is this correct?

Thanks,
Craig Green