First you must build all your Guvnor packages. If you have any fact model jars in Guvnor, you have to put those in the $jbpm-installer/dependencies dir and then run "ant clean.demo" and "ant.install.demo" or "ant.install.demo.noeclipse" and then "ant start.demo" or "ant start.demo.noeclipse".
We fixes some package detection issues in jBPM 5.3 which has just released, for example in 5.2 you pretty much have to build your packages before you access the jbpm console, if you access console before you build your packages, it will not be able to detect them after. With 5.3 you should be able to do that and also console should be able to detect new packages as well that include process definitions (and have been successfully built). With 5.3 another thing that we fixed is the issues if some of your packages are not build (they will simply be ignored instead of raising issues during the console kbase building).
I would in your case give jBPM 5.3 a try as things are somewhat easier to work with and let us know what you run into.