I thought why not try rendering across the gigabyte lan?
Now this windows share IS public and I even turned off windows firewall.
Using Nautilus in Ubuntu, I can do whatever I wish file wise.
KEDnlive is complaining, so what else needs to be done?
also this directory already exists, so the error message is misleading.
screenshots
https://lh3.googleusercontent.com/-iqdMc2Ma-ZQ/UOlfxM11zBI/AAAAAAAAEU4/g...
https://lh5.googleusercontent.com/-rfkXskF7s1k/UOlfxFwb5WI/AAAAAAAAEU8/C...
https://lh4.googleusercontent.com/-4lqWUHVmdb4/UOlhKT1RiVI/AAAAAAAAEVk/b...

I am completely out of hard drive space, so I thought to try this.
I am getting a new 1TB sata3 to put in my PC, so then wont be an issue.
I am rendering a 26gb vid at the moment, when that is done in 4 hours, I will try your idea.
I put the movflags=quickstart arg in this one to see if youtube stops fussing.