Here's the latest beta Give it a try. For licensed users upgrades are free for up to six months from purchase date. After that, VP will continue to fully function but a fee will be required in order to register the newest. Retain your old install file and registration info.
If the problem isn't solved, try AVI export instead of Mp4.
If STILL no joy, please upload and share your work so someone here can analyse the project. It's easy, takes but a few minutes 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.