If I understandhttp://jclouds.incubator.apache.org/documentation/userguide/vmware-vcloud/, theerror message is OK as neither 1.5 nor 5.1 vCloud versions are supported.
Could you try the vcloud-director API, which is still in labs? https://github.com/jclouds/jclouds-labs/tree/master/vcloud-director http://search.maven.org/#search%7Cga%7C1%7Ca%3A%22vcloud-director%22That should support 1.5. There are also some threads about 5.1 work, although that seems to be still ongoing:
http://apache.markmail.org/thread/wv3fiaqy42lwm52h https://groups.google.com/forum/#!msg/jclouds-dev/QaEb9KRoK7o/M8GQJiOr-zwJ ap
