we've recently patched the code upstream in fabric8 to handle profiles that don't exist a little better. I think the issue is the "cxf" profile no longer exists; try "feature-cxf" which is the 6.1 name of it.
JBossFuse:karaf@root> fabric:profile-create --parents feature-cxf gs-cxf-base
Yeah I think there is a known issue when you specific a profile name that does not exists, then you get a NPE.
Possible this ticket