Does someone know how to work with this packet (175). It's for construction, but my attempts at sending a secondary map region result in a client crash.

I doubt it'll be much information if I add the stacktrace of the exception but nonetheless, here you are:
Code:
java.lang.ArrayIndexOutOfBoundsException: 500
	at media3D.render.TerrainRenderer.createNewCullingCluster(TerrainRenderer.java:1412)
	at media3D.media.landscape.TempMap.method46(TempMap.java:328)
	at execution.GameApplet.updateMapBuffers(GameApplet.java:944)
	at execution.cycles.LogicCycle.executeClientLogic(LogicCycle.java:60)
	at execution.cycles.ClientCycle.prepareAndExecuteClientLogic(ClientCycle.java:65)
	at execution.cycles.ClientCycle.executeCycles(ClientCycle.java:43)
	at execution.GameApplet.run(GameApplet.java:1207)
	at java.lang.Thread.run(Thread.java:745)