vWorkspace only supports English OS. If you try to create the Website on a different OS, you'll have to make some modifications, otherwise you'll see errors such as "Some or all ID references cannot convert"
Account names like "Network Service" have a different name so the creation fails to find them.
To get it working for now, until moving onto an English OS,
1. Create a local group called "Network Service"
2. Add NetwerkService or SERVICIO DE RED or NETZWERKDIENST to the group
3. Rename gebruikers or usuarios or Benutzer to Users
At this point, if you try to create, you'll get another error that translates to "Unknown Error: 0x80005000"
4. In IIS, Rename StandaardWebsite to Default Web Site (Or create a new Default Web Site)
5. Now it works!