Hi Davide,
The "library not found" errors indicate that the portal jar file "ca.apm.fieldpacks.agent.WebSphere Portal Extension.jar" is not in the correct location (/core/ext) so the classes referenced by pbds/pbls cannot be found. There was a similar thread here on how to configure the WebSphere Portal marketplace download where my colleagueDavidLewis advised similar:
"All I remember from the implementation is you need to put pbd/pbls in the core/config folder and specify in the agent profile, and add the agent jar file to the /core/ext folder.
A while ago, it used to be necessary to copy the agent extension jarfile to the /shared/app folder (or similar name) into the WAS Portal install itself, but that requirement was removed in any option that is currently available."
If you start the Agent with DEBUG enabled in agent profile (log4j.logger.IntroscopeAgent=DEBUG, logfile) it should show the (attempted) loading of the jar file
Hope that helps
Regards,
Lynn