You've somehow got some stray clips out beyond your movie.
Press the \ button (above the Enter key) on your keyboard so that your entire timeline can be seen at once. Most likely you'll see your movie plus a lot of dead air.
Click and drag your mouse over this "empty" area of your timeline and then press the Delete key on your keyboard.
Press the \ button again and you should be left with just your movie.
1. In the Expert workspace, expand (to max) the Timeline with the -+ slider above the Timeline.
2. Hit the End key of the keyboard.That should take you to this 26 minute mark on the Timeline where you believe you have nothing there.
3. Inspect the area for very thin black vertical lines scattered among the track(s) content. Delete all of them that you find. Check all tracks for these leftovers as well as for whole clips that may have been misplaced beyond the Timeline content wanted.
4. Then hit the End key again. This time it should go to the end of the Timeline content intended for export.
Please let us know the results.
I did not see SG post until after I posted mine. We are all targeting the same probable cause of your reported issue.
You were exactly right! Thank you very much, it worked.
[Excessive quotations removed for clarity - Hunt]
We are very pleased with your good news of success. Great job.
Continued success. Please do not hesitate to ask if questions or to ask for clarification on anything written.
Thanks for taking time to let us know the outcome.
Those Orphans can be very pesky, and trip up many. That Tips & Tricks article, that John T. linked to, goes into some of the details on how it can happen.
Good luck, and thank you for your report of success.
I will clean up your reply a bit, as it appears that your posted from an e-mail client, which did a full quotation of the post, to which you were replying. This bit of "housekeeping" will make it easier for others, with the same problem, to follow along more easily, later.