ofp: NullPOinterException when using sal-flow:remove-flow

odl: http://nexus.opendaylight.org/content/repositories/opendaylight.snapshot/org/opendaylight/integration/distribution-karaf/0.3.0-SNAPSHOT//distribution-karaf-0.3.0-20150513.081108-1551.tar.gz

installed features: odl-openflowplugin-flow-services-rest-li

the sal-flow:remove-flow returns http status 500

{"errors":{"error":[

{"error-type":"rpc","error-tag":"partial-operation","error-message":"The operation was cancelled while executing."}

]}}

steps to reproduce:
1) use sal-flow:add-flow to install a flow from test/csit/variables/xmls/f1.xml
2) then remove it (500 is recevied)