Ravenwolfe is correct, you need to update your ServUO core and compile a new exe.
The initial VNc repository commit was:
"Vita-Nex: Core 3.0 for RunUO 2.7 and ServUO 55"
I had anticipated that the current ServUO repository would have hit that publish milestone, but it basically means you need the latest 54 minimum.
Where do you get ServUO Pub 55? atm from The ServUO Repo link is Pub 54 which is what i am running atm ..from the looks on The Repo Link Pub 55 is only 80% complete