What Videopad version is being used? Look at the left-bottom corner of the window.
Install this one.
For one-time licensed users upgrades are free for up to six months from purchase date. After that, VP will continue to fully function but a fee is required in order to register the newest. Retain your old install file and registration info. If there's an issue, you can always revert.
After saving AS, with a unique # or name, close VP. Then relaunch it and click OPTIONS | DISK tab. Clear Unused Cache Files. Now try the export again.
To Save Project File AS, click the caret to the right of the Save Project icon on the toolbar. 