Close the server, open Blockland.exe, and in the start a game menu, remove the password. Click cancel, then quit.
Open the dedicated.bat file, and there will no longer be a password.
For future references, please only give administrator status to people you know you can trust, and wont cause harm to the server, no matter who they are.
You can also use the External Server Control program I have created to manage the settings of a dedicated server.
If you have basic knowledge of the console, you can also use:
$Pref::Server::Password = "";
in the dedicated server console. (Not the blockland window ~ console, the black dedicated server command line console)
