How to load a missing library

When I load the example ws_eliza.oml I get errors which look to me as if I am missing a library:

Description Resource Path Location Type
Adapter "INVOKE" has an invalid Component-Type reference: system.router.CT_INVOKE ws_eliza.oml JOperaTry1 Eliza.INVOKE JOpera Problem

I have enabled all available libraries in the JOpera library path setting, but I am not sure which library I am missing and where to find the right plug-in for it

I am using Eclipse: Version: 3.4.0
Build id: I20080617-2000
and JOpera 2.3.7

Thanks for your support

Missing Web Services Feature

This error occurs if the Web Services feature has not been installed.

WS invokation features are missing in 2.4.1

I'm having the same problem in JOpera 2.4.1. the problem is described here: