Invite is not working (anymore?)

However, I encounter issues with the dedicated server.
First; the game is shipped with a 32bit Java JRE, which complains about out of memory exceptions due to the 1024M limit.
second; the default .exe files ignores the lib path(?) which causes execeptions because 'jinput-dx8' etc. could not be found.

So in the end iam running the main game via:
java.exe -Djava.library.path=%cd%\lib\native;%cd%\lib -Xmx4096M -XX:MaxPermSize=2048M -cp game.jar com.zarkonnen.airships.Main

All good, until I try to join my dedicated server;


Init ResChooserScreen
Init AirshipGame
No Monkey
Checking for FBO
Done checking for FBO
Loading screen inited
Loading game data...
Checking mods
Loading game data complete
Memory check: 897
Loading game data complete
main menu inited
Memory check: 1385
Memory check: 1362
java.lang.RuntimeException: Attempting to access closed sheet.
at com.zarkonnen.airships.SpritesheetBundle.getTex(SpritesheetBundle.java:45)
at com.zarkonnen.airships.Appearance.lockShader(Appearance.java:505)
at com.zarkonnen.airships.BackdropVisualLayer.draw(BackdropVisualLayer.java:80)
at com.zarkonnen.airships.UniScreen.render(UniScreen.java:1264)
at com.zarkonnen.airships.AirshipGame.render(AirshipGame.java:1235)
at com.zarkonnen.catengine.SlickEngine.render(SlickEngine.java:113)
at org.newdawn.slick.GameContainer.updateAndRender(GameContainer.java:703)
at org.newdawn.slick.AppGameContainer.gameLoop(AppGameContainer.java:456)
at org.newdawn.slick.AppGameContainer.start(AppGameContainer.java:361)
at com.zarkonnen.catengine.SlickEngine$MyAppGameContainer.runUntil(SlickEngine.java:148)
at com.zarkonnen.catengine.SlickEngine.runUntil(SlickEngine.java:169)
at com.zarkonnen.airships.Main.main(Main.java:66)
java.lang.RuntimeException: Attempting to access closed sheet.

Any suggestions?

Because the normal way didn't work (as stated in my previous comment; errors about memory etc.), haven't checked if it works after the latest update(s) because I already lost my interest.