Like other people said(just expanding on it), just bypass gameforge live by going in your RoM folder and dragging the Client - Shortcut to your desktop (or opening it) and then pin RoM to your taskbar and then click on it and start 1 client, and then right click it and select the program again to start a second one and then you're good to go.

Hope that helps! And make sure you're on windowed mode.