I created a moderately complex BPMN model in BPA tool and tried to export it (SOA -> Share menu). I chose to have a validation before sharing and the my model tranformation fails with this error:
JavaException: oracle.bpa.common.exception.BpaException: BPAEXC-19002 - Error while Transforming the BPMN process to BPEL process
There are cross edges in the BPMN Model
Remove the crossedges in the BPMN model
Without looking at the model, it is really hard to tell. If you don't mind, please upload the model.
On the other hand, generally, BPEL and BPMN are not totally compatible. In current implementation of BPMN to BPEL/BPMN transformation, things like cross edges, callable process, bpmn process containing event subprocess, etc. do not have BPEL counterparts. Therefore, there will be errors during transformation.