Unable to start WSO2 Business Process Server

Question

I'm trying to start up the BPS that comes with WSO2 EI 6.1.1.

However, it gives the following error:

WARN {org.wso2.carbon.core.init.CarbonServerManager} -  Carbon initialization is delayed due to the following unsatisfied items: {org.wso2.carbon.core.init.CarbonServerManager}
WARN {org.wso2.carbon.core.init.CarbonServerManager} -  Waiting for required OSGi Service: org.wso2.carbon.bpel.core.BPELEngineService {org.wso2.carbon.core.init.CarbonServerManager}
WARN {org.wso2.carbon.core.init.CarbonServerManager} -  Waiting for required OSGiAxis2Service: org.wso2.carbon.bpel.deployer-4.4.15 {org.wso2.carbon.core.init.CarbonServerManager}
WARN {org.wso2.carbon.core.init.CarbonServerManager} -  Waiting for required Deployer: BPELDeployer {org.wso2.carbon.core.init.CarbonServerManager}
WARN {org.wso2.carbon.core.init.CarbonServerManager} -  Waiting for required OSGiAxis2Service: org.wso2.carbon.bpel-4.4.15 {org.wso2.carbon.core.init.CarbonServerManager}
WARN {org.wso2.carbon.core.init.CarbonServerManager} -  Waiting for required OSGi Service: org.wso2.carbon.humantask.core.HumanTaskEngineService {org.wso2.carbon.core.init.CarbonServerManager}
WARN {org.wso2.carbon.core.init.CarbonServerManager} -  Waiting for required OSGiAxis2Service: org.wso2.carbon.bpel.b4p-4.4.15 {org.wso2.carbon.core.init.CarbonServerManager}

Any tips or suggestions on what to try are much appreciated.