Has this course retired? If yes, then which course covers training on VPN 3000 Concentrators?
There is no replacement exam for 642-511.
There are other certs converying a wide range of VPN concepts, I would suggest to look into CCSP track.
Also you may find a larger audience in certifications and training forums under the Career Certifications discussion in main netpro page, there you may find rich information on your training certs concerns.