Problem with a ClassNotPersistenceCapableException

[Michael Gysi-Gander]

Hi
 
We have a problem when attempting write to the db - what we get is
 
org.apache.ojb.broker.metadata.ClassNotPersistenceCapableException: Could not init 
Identity for given object class ch.mypackage.Person: Object has been modified by 
someone else] 
 
What is happening here? I get the same error when I attempt to insert a new "Person" 
record
 
thanks for any help
cheers
Mike