I constantly encounter the same annoying problem. When I finally get to the point where I'm going to build my DVD Encore tells me there have been errors discovered. When I view the errors, it tells me that, for my timeline, the end action is not set, but the end action IS set. I set the end action to "Stop." When I ignore the problem and continue the build, the DVD comes out fine. Like I said, it seems to be more annoying that a real obstacle, but I'd like to figure out what's going on. Anyone else encounter this?
Like Joe said, you can safely ignore this message if the end action is set to stop. I've found that if you set the end action to anything else, check for errors and then set the end action back to stop the "error" is no longer reported.