我正在尝试遵循本教程：
https
://docs.wso2.com/display/AM1100/Adding+an+API+Subscription+Workflow
但是当我尝试从商店注册订阅时，在 BPS 控制台中我收到以下错误：
[2016-06-28 11:21:10,729] WARN {org.wso2.carbon.bpel.b4p.extension.PeopleActivity} - SOAP Fault: <?xml version='1.0' encoding='utf-8'?><soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"><soapenv:Header xmlns:wsa="http://www.w3.org/2005/08/addressing"><wsa:Action>http://www.w3.org/2005/08/addressing/soap/fault</wsa:Action><wsa:RelatesTo>urn:uuid:fd3c1de4-2689-4743-bfad-a31de7d726af</wsa:RelatesTo></soapenv:Header><soapenv:Body><soapenv:Fault><faultcode>soapenv:Server</faultcode><faultstring>java.lang.NullPointerException</faultstring><detail/></soapenv:Fault></soapenv:Body></soapenv:Envelope>
在 BPS 日志中，我也有此错误，但我找不到有关如何生成 Nullpointer 的信息：
[2016-06-28 11:21:10,767] WARN {org.apache.ode.bpel.engine.BpelProcess} - Instance 1101 of {http://workflow.subscription.apimgt.carbon.wso2.org}SubscriptionApprovalWorkFlowProcess-2 has completed with fault: FaultData: [faultName={http://docs.oasis-open.org/ns/bpel4people/bpel4people/200803}nonRecoverableError, faulType=null ({http://docs.oasis-open.org/ns/bpel4people/bpel4people/200803}nonRecoverableError: <?xml version='1.0' encoding='utf-8'?><soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"><soapenv:Header xmlns:wsa="http://www.w3.org/2005/08/addressing"><wsa:Action>http://www.w3.org/2005/08/addressing/soap/fault</wsa:Action><wsa:RelatesTo>urn:uuid:fd3c1de4-2689-4743-bfad-a31de7d726af</wsa:RelatesTo></soapenv:Header><soapenv:Body><soapenv:Fault><faultcode>soapenv:Server</faultcode><faultstring>java.lang.NullPointerException</faultstring><detail/></soapenv:Fault></soapenv:Body></soapenv:Envelope>)] @108 {org.apache.ode.bpel.engine.BpelProcess}
有什么想法？