thanks Michael,
I've not fully understand why i need to patch 4.5, I simply downloaded from maven repository (i'm not building from source, so it's difficult for me to patch).
If database is changed in some way, may I hadn't see the errors during test which involved schema generation (or am I wrong?). If there are some mismatch between code in org/jbpm/pvm/internal/history/model/HistoryTaskImpl and the mapping file jbpm.history.hbm.xml, can you please point out where I must apply changes? only jbpm.history.hbm.xml