So did a little testing... and I get this when I bomb a factory with Production Tech.
Looks like the error is related to the game looking for an icon... guessing I have to add the damaged units into the Icon Properties list.
TripleA engine version 1.9.0.0.10506
Loading map: total_world_war, from: C:\Users\Hepster\triplea\downloadedMaps\total_world_war-master\map
Loading resources from the following paths: [C:\Users\Hepster\triplea\downloadedMaps\total_world_war-master\map, C:\Program Files\TripleA\assets]
Loading map: total_world_war, from: C:\Users\Hepster\triplea\downloadedMaps\total_world_war-master\map
Loading resources from the following paths: [C:\Users\Hepster\triplea\downloadedMaps\total_world_war-master\map, C:\Program Files\TripleA\assets]
Error: java.lang.NullPointerException
java.lang.NullPointerException
at javax.swing.ImageIcon.<init>(Unknown Source)
at games.strategy.triplea.image.DiceImageFactory.getDieIcon(DiceImageFactory.java:168)
at games.strategy.triplea.ui.DicePanel.create(DicePanel.java:68)
at games.strategy.triplea.ui.DicePanel.setDiceRollForBombing(DicePanel.java:37)
at games.strategy.triplea.ui.BattleDisplay.bombingResults(BattleDisplay.java:165)
at games.strategy.triplea.ui.BattlePanel.lambda$bombingResults$17(BattlePanel.java:428)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Error: java.lang.NullPointerException
java.lang.NullPointerException
at javax.swing.ImageIcon.<init>(Unknown Source)
at games.strategy.triplea.image.DiceImageFactory.getDieIcon(DiceImageFactory.java:168)
at games.strategy.triplea.ui.DicePanel.create(DicePanel.java:68)
at games.strategy.triplea.ui.DicePanel.setDiceRollForBombing(DicePanel.java:37)
at games.strategy.triplea.ui.BattleDisplay.bombingResults(BattleDisplay.java:165)
at games.strategy.triplea.ui.BattlePanel.lambda$bombingResults$17(BattlePanel.java:428)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)