DVD Talk Forum - "Unauthorized" Chaplin Essanays?

Here's an odd question I hope someone might be able to help me with. I recently got the Image DVD set of Chaplin's Essanay and Mutual shorts, and figured I'd put some of my old VHS tapes up for bid on Ebay. I sold my set of Blackhawk Mutuals with no problem (and I've also sold Chaplin on Magnetic Video, Key Video, and Playhouse Video with no problem), but when I put up a lot of two tapes, one of 4 Essanays from Alpha Video and another of two Essanays from Video Yesteryear, Ebay pulled the auction after a day, telling me that I was selling "unauthorized" material. Try as I might, I could get no further details from them, nor could I learn who had complained so that I could contact them directly and learn what the problem was. So which was the infringing item? Alpha, Video Yesteryear, or both? And why? I thought these films had been released in public domain versions for quite some time. It's not that I'm concerned about the loss -- after all, I'd only have gotten a few bucks for them -- but I'd like to know why these items are considered illegal. Anyone know? Thanks.