I suspect it is because I have a "stop" menu marker only one or two frames before a "main" menu marker. This is because I've always been uncertain just how you are supposed to use these two markers together.
I have three 'main movies' on the timeline. I don't have any scenes as such and don't have any scene markers. I want the DVD menu to show the three movies on the first screen (and not show any scene selection item). The menu template I chose does just this - no problem there. After selecting one of the main movies, I want it to play that movie and then return to the main menu so the user can choose another movie (not scene). This works also.
So I (logically?) put a stop marker on the last frame of one movie and a main menu marker on the first frame of the next movie. How else are you stupposed to do this? What is the specification the warning is referring to? Things are working, but I'm worried about the warning.
I got exactly the same: a message ('A few Menu Markers are closer than they are required by Specification') while everything works fine. Seems that the only thing wrong (or confusing) is this error message in the Events window. Perhaps best to enjoy this as a nice exception to the rule ;-)