Loading this savegame of a WWIIv6 variant I made, with all players assigned to Medium (AI), you get this crashing error:
Medium AI (Round 1 Russians Purchase Units):
Exception in thread "Triplea start thread" java.lang.NullPointerException
at games.strategy.triplea.ai.strongAI.StrongAI.purchase(StrongAI.java:7151)
at games.strategy.triplea.ai.AbstractAI.start(AbstractAI.java:427)
at games.strategy.engine.framework.ServerGame.waitForPlayerToFinishStep(ServerGame.java:564)
at games.strategy.engine.framework.ServerGame.runStep(ServerGame.java:458)
at games.strategy.engine.framework.ServerGame.startGame(ServerGame.java:281)
at games.strategy.engine.framework.startup.launcher.LocalLauncher.launchInNewThread(LocalLauncher.java:74)
at games.strategy.engine.framework.startup.launcher.AbstractLauncher$1.run(AbstractLauncher.java:47)
at java.lang.Thread.run(Unknown Source)