Your Work Area Bar is likely longer than your movie. This could be because a "phantom frame" is floating out on your timeline some place.
Press the \ key (above the Enter key) so that you can see your whole Work Area Bar. Is it extended to 5:47?
Click and drag your mouse over the timeline beyond your movie. You should snag some random frames. Delete them until your Work Area Bar (the gray bar along the top of your timeline) snaps back to 4:59.
I found that fantom clip.
(Now I remember moving the clip out there as a temporary holding spot, but I had inadvertently shrunk it down to an invisible spot.)
Glad we could help, Michael.