The sounds used were bought from pond5.com, royalty free. I don't know if this is a problem, but I couldn't find many good and free sounds elsewhere. I'm not quite sure what you meant about your quote, though. :s
Royalty-free is a problem.
When you buy sounds, you get a license for yourself, but you don't get a license for others. That means you can use a sound in your own project, but you can't relicense the sound under an open-source license or bundle it in open-source software.
If you can't find a good sound, you can just publish the video without sound. Maybe someone will step up and create a sound or find an open-source sound. If not, perhaps CorsixTH can use the sounds from the original game for now, like it does with graphics.
BTW, are all the objects in your video open-source? Are you complying with their license?