I've had that happen several times. I've also had the browser try to open it as a text file and show all the gibberish instead of downloading it. I couldn't figure a way to get around it on my NT. They give you the option to 'save as' on my PC, so I do that and side load them. I'm guessing that the MIME-type is set to somethimg that the Nook browser doesn't recognize as an epub. The same files don't work in Dolphin either.
