As mentioned a couple of times, that VNC Viewer error is indicating that it can't access a .vnc file:
Have you tried to manually 'walk the path' through:
\\slcgateway01.dealersocket.net [other screenshots for slcgateway01 don't include .dealersocket.net ... please make sure you include it when you attempt manually to make sure you're attempting in the same way that the scripts are attempting)
Then go to: hol build
Then go to: AWS VNC Files
Then attempt to manually open: HOL-Ta'Shumbria.Miller-06.vnc
And see what happens?