Hmm...
Do you really sore CGLIB is in your CLASSPATH?
Show, please, StackTrace now.
And there is another solution for you:
HTML Code:
<service-activator input-channel="channel1"
output-channel="channel2" ref="InsertService"
method="insertCustData">
<request-handler-advice-chain>
<tx:advice>
<tx:attributes>
<tx:method name="*" propagation="REQUIRES_NEW" rollback-for="java.lang.Throwable"/>
</tx:attributes>
</tx:advice></request-handler-advice-chain>
</service-activator>
From other side intruduction of service interface should fix your issue too...