The correct way to migrate a project is to click the FILE menu, then SAVE PORTABLE PROJECT AS. You might save the result to a USB stick.
Then insert the stick into PC #2 and click the .vpj file. Or open Videopad and open the project from the USB stick.
With this method, it's a sure thing that all files, and the correct paths to them, will be available on any PC.
If this doesn't solve the issue, post again.