Good news, .NET has an option I can take advantage of called "self-contained builds" which means Dreambox should now bundle the .NET runtime instead of relying on it being installed. Maybe give it a shot and see if it works now!
Windows version works now, though it's a bit laggy, might just be me. Linux version still returns the .NET error.
Sorry for being a dick, good luck in the future.
Hm, maybe I scuffed something up when building. Gimme a bit and I'll try and see if I'm doing the self contained build correctly.