https://issues.jboss.org/browse/JBPM-3321 - watch it if you want.
Regarding the other errors, I was getting things like:
Unable to Analyse Expression $startMessage[@subject = 'foobar']: [Error: reference to undefined interceptor: subject] [Near : {... $startMessage[@subject = 'foobar'] ....}] ^ [Line: 1, Column: 16]
These types of build errors go back to what I was saying about no out-of-the-box support in jbpm for BPMN2 expressions (those examples seem to use the XPath dialect).