Experiment with the ASPECT RATIO choices that are available in recent VP versions via a right-click on bin clips or via effects on bin or sequence clips.
Try letterbox. Also be sure that the export choice reflects that you want a wide-screen presentation.

If this doesn't solve the issue, upload and share your project and someone will check it out. It's easy, takes little time and can be private.
Here's how... http://nch.invisionzone.com/topic/23659-tips-for-getting-help-on-this-forum/
If it contains sensitive material link it in a personal message (PM). Click the envelope above. It won't be passed on or retained. Use FILE|SAVE PORTABLE PROJECT AS, not simply SAVE PROJECT, and don't forget to share it.