Two parts, looks like the TFTP is being blocked on the @#$@ Windows machine. need to research the firewall rules, as I thought I created one to open up for the app, but see this on the network;
14:41:06.876932 STP 802.1w, Rapid STP, Flags [Learn, Forward], bridge-id 8000.00:18:0a:53:a4:54.800e...