What version of Videopad is being used?
Exported your project (sequence 2 only) from beta v7.33 and there was no hesitation when played in Windows Media Player or MPC-HC.
Deleted a snippet of extraneous video at the end and exported once again with the same result.
If you are running a Windows PC, consider trying that test version, while keeping in mind that it is subject to change and may have undiscovered bugs.
For licensed users upgrades are free for up to six months. After that, VP will continue to fully function but a fee will be required in order to register the newest.