Copyrighting tracks with vocal samples

Dear Rich: I would like to ask about pre-licensed sample packs. I purchased a CD with vocal samples, in the licensing agreement there was information that "You can use the sounds in any type of non commercial music production without permission." So I asked the producer of the samples if I can use them freely in commercial production and he agreed. When I finished the track I copyrighted it. But because the track has the vocal samples and they are quite popular if I release my track may I have a conflict with other producer as to "who came first?" You won't run into any disputes over the samples.Copyright law doesn't care who came first. All that matters is whether you copied somebody's work without permission. Keep in mind that if the only thing in common between your recording and someone else's is the fact that both of them use the same licensed samples, there is no infringement. You can both co-exist in sampled harmony.
The good and the bad. The great thing about licensed samples is that you have inexpensive access to great sounding audio clips. The downside is that anybody else can also purchase the same rights, and end up sounding like your tracks. (Just like anybody can license the same photo in their blog as the one we licensed from istockphoto.) By the way, if you register your new tracks, the Dear RIch Staff suggests that you state that you are not claiming rights to the samples (in section 4 of Form CO).