I installed all plugins named workflow-xx (was that right??)
and tried to define a workflow job.
However the configuration screen does not allow me to enter a workflow definition.
When I press save I get a NPE.
So I cannot use the plugin at all.

java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.kohsuke.stapler.Function$InstanceFunction.invoke(Function.java:298)
at org.kohsuke.stapler.interceptor.RequirePOST$Processor.invoke(RequirePOST.java:46)
at org.kohsuke.stapler.Function$InterceptedFunction.invoke(Function.java:399)
at org.kohsuke.stapler.Function.bindAndInvoke(Function.java:161)
-------------------------

Caused by: java.lang.NullPointerException
at org.jenkinsci.plugins.scriptsecurity.scripts.ScriptApproval.hash(ScriptApproval.java:314)
at org.jenkinsci.plugins.scriptsecurity.scripts.ScriptApproval.configuring(ScriptApproval.java:357)
at org.jenkinsci.plugins.workflow.cps.CpsFlowDefinition.<init>(CpsFlowDefinition.java:76)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:525)
at org.kohsuke.stapler.RequestImpl.invokeConstructor(RequestImpl.java:447)
at org.kohsuke.stapler.RequestImpl.instantiate(RequestImpl.java:699)
at org.kohsuke.stapler.RequestImpl.access$200(RequestImpl.java:81)
at org.kohsuke.stapler.RequestImpl$TypePair.convertJSON(RequestImpl.java:596)
at org.kohsuke.stapler.RequestImpl.bindJSON(RequestImpl.java:400)
at org.kohsuke.stapler.RequestImpl.bindJSON(RequestImpl.java:396)
at org.jenkinsci.plugins.workflow.job.WorkflowJob.submit(WorkflowJob.java:156)
at hudson.model.Job.doConfigSubmit(Job.java:1188)
... 83 more