Hi,
yes, ant script is good way of doing deployments.
Based on what I can see in your ant script it misses resources to be included in the jar archive. At the moment you only include jpdl.xml files regardless of package location. You should include your classes exactly the same way.
Here is how it should look like. In addition, please include any other resources as well (such as task form .ftl, rules definition .rtl)
<jar destfile="${jbpm.home}/eclipse/workspace/PETest1/target/PETest1.bar">
<fileset dir="${jbpm.home}/eclipse/workspace/PETest1/src">
<include name="**/*.jpdl.xml" />
<include name="**/*.class" />
</fileset>
</jar>
HTH
Maciej