Reading over the last few posts, I think it's interesting how many people tend to believe that the very human Catholic Church has the ability to cancel 'Holy orders' (which I take to mean the validity of another church's work in God through different services). I don't think God bestowed that particular power upon any human, regardless of their pedigree.
In fact, I think Jesus speaks against that type of behavior in Mark chapter 9:
38)And John answered him, saying, Master, we saw one casting out devils in thy name, and he followeth not us: and we forbad him, because he followeth not us.
39)But Jesus said, Forbid him not: for there is no man which shall do a miracle in my name, that can lightly speak evil of me.
40)For he that is not against us is on our part.
41)For whosoever shall give you a cup of water to drink in my name, because ye belong to Christ, verily I say unto you, he shall not lose his reward.
I know that isn't
specifically talking about 'Holy orders', but I think the parallel is close enough for us to realize the point of the section is to say 'Do not impede the work of God in others just because they do not belong to the same club as you'.
It's interesting that, for the true Church, it took all the way up to Vatican II for there to be the understanding that a non Catholic Christian will not 'lose his reward', despite what Jesus clearly said.
I don't expect to change anyone's opinion on the subject, but just food for thought