Preventing Loading of a Mission

I am trying to have my clients register before they play. Here is what I have. I have added a button on the main menu that says Register. When you click on it the button loads up another GUI that has Username and Password in it along with a button that says Register. When I click register it does the following command.

function createAccount()
{

    if(!isObject(ServerConnection))
    {
        connect($Pref::Primary::Server);
        schedule(1000,0,createAccount);
        return;
    }
    CommandToServer('CreateAccount',$Pref::Account::Name,md5($Pref::Account::Password));
}

Here is the connect function JIC it helps.

function connect(%server)
{
    if(!isObject(ServerConnection))
    {
        echo("Server is "@%server);
        new GameConnection(ServerConnection);
        ServerConnection.connect(%server);
        $localAdmin = false;
    }
}

Now as soon as I hit Register it starts in on the loading progress screen. Within a second though it pops up a dialog box that says Account was Registered. Thx. Here is the part of the server script it is calling that from.

CommandToClient(%client, 'HandleMSG',"MSGACCOUNTCREATESUCCESS");

Which is loading this function.

function ClientCmdHandleMSG(%msg)
{
    %msg = detag(%msg);
    switch$(%msg)
    {
    case "MSGACCOUNTCREATESUCCESS":
        MessageBoxOK("Success!", "Your Account has been created!");
        //should bring back to MainMenu automagically
etc...

What I am wanting to do is stop it from loading any mission and just return the box.

Thanks