You can change GM level via SQL, -> in your GameDB -> Click the "-" symbol, then find tables and click the "-" and then find dbo.account -> Right click "Edit Rows" and change under "GM" column to 99 which will set it's Account level to GM rights. As for GM commands, I think your GameServer.exe is not compatible, or maybe try this in your server files. Or maybe it's your client StringSet.txt, or the Port with client. (Note might not work, as I do not know where you got your exe's from.
Go to GameServer folder -> resource-> scripts -> calculate -> functions.lua and put
function HandleChat(role, message)