Hello,
You have to either tweak the build.properties and build.xml files and use start.demo or do manually the work that build.xml does.... I'll try to guide you with tweaking build.properties and build.xml ;)
First of all make a safety backup copy of your existing jboss installation i.e. copy your jboss directory .
Edit build.properties and set the property jboss.server.version with the version of your jboss installation, the property jboss.home with the path to your jboss installation.
Edit build.xml and replace the line,
<target name="install.demo" depends="install.jboss,install.guvnor.into.jboss,install.designer.into.jboss,install.jBPM-gwt-console.into.jboss,install.eclipse,install.jBPM-eclipse.into.eclipse,install.jBPM.runtime,install.drools-eclipse.into.eclipse" />
with the line,
<target name="install.demo" depends="install.guvnor.into.jboss,install.designer.into.jboss,install.jBPM-gwt-console.into.jboss,install.eclipse,install.jBPM-eclipse.into.eclipse,install.jBPM.runtime,install.drools-eclipse.into.eclipse" />
in other words delete the install.jboss part from the depends attribute value.
Now you may try to run ant install.demo and then ant start.demo .
If you get any exceptions stop the procedure (although ant will probably stop running) and post the exceptions here for further instructions :)