auto increment not working

[Nilesh]

In my OJB (using  PersistenceBroker ) application auto-increment is not working.

I am using  MySQL in which I have also used the auto-increment constraint for the 
Primarykey ( bigint(20) ) 


For my database definition i have used the "SequenceManagerNativeImpl" 

 <sequence-manager 
className="org.apache.ojb.broker.util.sequence.SequenceManagerNativeImpl">
            <attribute attribute-name="autoNaming" attribute-value="true"/>
 </sequence-manager>


also in the mapping file  i have

    <class-descriptor class="com.haystack.emailmarketingchoice.member.MemberVO" 
table="tblMember">

       <field-descriptor id="1" name="memberId" column="member_id" jdbc-type="BIGINT"  
primarykey="true" autoincrement="true" access="readonly" />
        ------------
        ------------
    </class-descriptor> 

i have also tried without the  --> access="readonly"

but it generates a new 20 digit  "auto-increment" number  only for the first insert, 
for the subsequent inserts it generates the same number and a Duplicate Entry error 
arises.

I have also tried the following sequence managers

SequenceManagerMySQLImpl
SequenceManagerSeqHiLoImpl

with and without these attributes
  <attribute attribute-name="grabSize" attribute-value="5" />
  <attribute attribute-name="globalSequenceId" attribute-value="true"/>
 <attribute attribute-name="globalSequenceStart" attribute-value="10000"/>



But ALL Failed.
Have any one of you tried this. Please let me know.
Thanks in advance for your interest in my problem.

Regards,
Arjun.