My experience was the same as so many others.... but it started, i have to admit, with feeding Crane stationery-grade paper in the secondary feeder, which jammed and then tore when I tried to remove it. I thought I had gotten it all when the HP message went from "paper jam" to "no paper pickup." I had the service person come out the next morning, and we tore the machine apart. Thanks to these posts, we persisted until we found the 1"x 1.5" remaining fragment on a roller. We discovered it when we opened the cover, removed the toner, then partially closed the cover so that we could see above and below the separator. In fact, the machine spit it out for us.
Ok, HP could be perhaps be more logical in their user messaging... but golly, these old machines are smart. If you are getting any kind of error message, there is a scrap of paper somewhere in that baby.