Here's a quote from my JK2 editing guide:
"If you get an error message saying some "bone" cannot be found, it means that bone shouldnt have any weights assigned to it, BUT it is still included in the bones list, carcass will not find bones if they are not added in the bones list but there are some exception, see "specific weighting"."
go there if you want to get the whole tuts:
http://www3.sympatico.ca/psykopat/)