Can't generate primary key values for given Identity

hello list,

i've used ojb several times before, but now i am in trouble with ojb.
I have the following problem. I am using ojb in cocoon try to store
Objects from a flow controller.

If I store my Object to database, I get a PersistenceBrokerException: 
Can't generate primary key values for given Identity .

I am using Java5 and the HSQLDB shipped with cocoon. My mapping looks like:

<class-descriptor class="de.rim.model.Kunde" table="KUNDE">
  <field-descriptor name="id" column="ID" jdbc-type="INTEGER" 		
	primarykey="true" autoincrement="true">
  <field-descriptor name="vorname" column="VORNAME"
  <field-descriptor name="adresse" column="ADRESSE" jdbc-type="VARCHAR"/>
  <field-descriptor name="plz" column="PLZ" jdbc-type="VARCHAR"/> 

  <field-descriptor name="ort" column="ORT" jdbc-type="VARCHAR"/>
</class-descriptor>

i tried it also with sequence-names, changing to postgres


[...]
Caused by: org.apache.ojb.broker.PersistenceBrokerException: Can't 
generate primary key values for given Identity 
org.apache.ojb.broker.util.sequence.HighLowSequence{kunde_id_seq} at 
org.apache.ojb.broker.util.BrokerHelper.getKeyValues(BrokerHelper.java:225) 
org.apache.ojb.broker.util.BrokerHelper.getKeyValues(BrokerHelper.java:192)
org.apache.ojb.broker.accesslayer.StatementManager.getKeyValues(StatementManager.java:679)
org.apache.ojb.broker.accesslayer.StatementManager.bindSelect(StatementManager.java:473)
org.apache.ojb.broker.accesslayer.JdbcAccessImpl.materializeObject(JdbcAccessImpl.java:570)
org.apache.ojb.broker.core.PersistenceBrokerImpl.getPlainDBObject(PersistenceBrokerImpl.java:1504)
org.apache.ojb.broker.core.PersistenceBrokerImpl.getDBObject(PersistenceBrokerImpl.java:1548)
org.apache.ojb.broker.core.PersistenceBrokerImpl.doGetObjectByIdentity(PersistenceBrokerImpl.java:1671)
org.apache.ojb.broker.core.PersistenceBrokerImpl.getObjectByIdentity(PersistenceBrokerImpl.java:1643)
org.apache.ojb.broker.core.DelegatingPersistenceBroker.getObjectByIdentity(DelegatingPersistenceBroker.java:357)
org.apache.ojb.broker.core.DelegatingPersistenceBroker.getObjectByIdentity(DelegatingPersistenceBroker.java:357)
org.apache.ojb.broker.util.sequence.SequenceManagerHighLowImpl.lookupStoreSequence(SequenceManagerHighLowImpl.java:296)
org.apache.ojb.broker.util.sequence.SequenceManagerHighLowImpl.getSequence(SequenceManagerHighLowImpl.java:267)
Caused by: java.lang.ArrayIndexOutOfBoundsException: 1
org.apache.ojb.broker.util.BrokerHelper.getKeyValues(BrokerHelper.java:214)