Well, if anything that the support told you to do have worked, I don't think that someone else in the whole forum will really help you to resolve your current problem (Also I don't think that the TCP ports will affect the problem of your lua dll, but I can be wrong).
If you didn't try before, I can propose you to install the game using the Gameforge launcher, but if you already have an account bounded to Steam, with some progression done, you will cannot retrieve your progression on the Gameforge client account (you will have to restart from 0). Maybe this will fix your problem, but I'm not sure.
And if you've already tried... Then rip I guess xd