Your fact model and dependency jars with 3rd party classes you use in your process/rules should be in jar files and put them in $installer/dependencies directory, then run
ant clean.demo
ant install.demo.noeclipse
ant start.demo.noeclipse
putting the jars in $installer/dependencies will assure that they are placed on the console classpath correctly.
Since the Drools .pkg file does not include jars you have to do this step manually.
Hope this helps.