Hello,
I use ACS 6.2-GA :

using Workflow Admin Console i tried to deploy a sample bpmn2.0 workflow file :
<?xml version="1.0" encoding="UTF-8"?>
<definitions id="definitions"
xmlns="http://www.omg.org/spec/BPMN/20100524/MODEL"
xmlns:activiti="http://activiti.org/bpmn"
targetNamespace="Examples" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.omg.org/spec/BPMN/20100524/MODEL http://www.omg.org/spec/BPMN/2.0/20100501/BPMN20.xsd">
<process id="osgiProcess" name="Osgi process">
<startEvent id="start" />
<sequenceFlow sourceRef="start" targetRef="serviceTask"/>
<serviceTask id="serviceTask" activiti:delegateExpression="${testBean}" />
<sequenceFlow sourceRef="serviceTask" targetRef="serviceTask2"/>
<serviceTask id="serviceTask2" activiti:delegateExpression="${activityBehaviourBean}" />
<sequenceFlow sourceRef="serviceTask2" targetRef="end"/>
<endEvent id="end"/>
</process>
</definitions>error is :
org.alfresco.service.cmr.workflow.WorkflowException: 11240036 Workflow Component for engine id 'activity' is not registered
Thank you for your help