```No X11 DISPLAY variable was set, but this program performed an operation which requires it.

No X11 DISPLAY variable was set, but this program performed an operation which requires it.
        at java.awt.GraphicsEnvironment.checkHeadless(GraphicsEnvironment.java:204)
        at java.awt.Window.init(Window.java:484)
        at java.awt.Window.<init>(Window.java:436)
        at java.awt.Window.<init>(Window.java:591)
        at java.awt.Dialog.<init>(Dialog.java:665)
        at java.awt.Dialog.<init>(Dialog.java:510)
        at javax.swing.JDialog.<init>(JDialog.java:422)
        at javax.swing.JOptionPane.createDialog(JOptionPane.java:945)
        at net.minecraftforge.installer.InstallerPanel.run(InstallerPanel.java:258)
        at net.minecraftforge.installer.SimpleInstaller.launchGui(SimpleInstaller.java:182)
        at net.minecraftforge.installer.SimpleInstaller.main(SimpleInstaller.java:154)