Commiting large transasctions (no replies)

Hi there,

We're trying to commit large transactions to MySql cluster using the ClusterJ api.
When committing 200.000 records everything is ok but when trying to commit 500.000 records the following error occurs.
"com.mysql.clusterj.ClusterJDatastoreException: Error in NdbJTie: returnCode -1, code 4.002, mysqlCode -1, status 1, classification 8, message Send to NDB failed ."
Can anybody help me out with this ?
Probably we have to increase some properties of the cluster but can anyone tell me which ones ?

Thanks in advance,
Arco